数组

两数之和

Two Sum is solved fastest by storing seen values in a hash map and checking each number's needed complement once.

寻找两个正序数组的中位数

Find the median of two sorted arrays using binary search for efficient O(log(min(m, n))) time complexity.

盛最多水的容器

Find two vertical lines that can form a container with the most water in a given array of heights.

最长公共前缀

Find the longest common prefix in an array of strings, returning an empty string if none exists.

三数之和

Given an integer array, return all unique triplets where the sum is zero using two-pointer scanning with careful duplica…

最接近的三数之和

Find the sum of three integers in an array that is closest to a given target using two-pointer scanning.

四数之和

The 4Sum problem requires finding all unique quadruplets in an array that sum to a specific target value.

删除有序数组中的重复项

Learn how to remove duplicates from a sorted array in-place using two-pointer scanning while preserving element order.

移除元素

Remove Element challenges you to remove a value from an array in-place using efficient two-pointer scanning and tracking…

下一个排列

Next Permutation is a medium-difficulty problem focusing on generating the next lexicographically greater permutation of…

搜索旋转排序数组

Find the index of a target in a rotated sorted array using a careful binary search that handles pivot shifts.

在排序数组中查找元素的第一个和最后一个位置

Locate the first and last index of a target in a sorted array using binary search for precise O(log n) performance.

搜索插入位置

Find the correct index for a target value in a sorted array using binary search, or return the position where it should …

有效的数独

Check if a 9x9 Sudoku board is valid by scanning rows, columns, and sub-boxes with hash lookups, ensuring no duplicates …

解数独

Solve the Sudoku puzzle by filling empty cells while respecting Sudoku's rules using array scanning and backtracking.

组合总和

Find all unique combinations of numbers from a distinct array that sum to a target using controlled backtracking search.

组合总和 II

Find all unique combinations of numbers that sum to a target using backtracking with careful pruning to avoid duplicates…

缺失的第一个正数

Identify the smallest missing positive integer in an unsorted array using constant space and linear time scanning techni…

接雨水

Calculate the total trapped rain water using the elevation map array, leveraging dynamic programming and two-pointer pat…

跳跃游戏 II

Jump Game II requires finding the minimum jumps to reach the end of an array using dynamic programming and greedy techni…

全排列

Generate all possible orderings of a distinct integer array using backtracking search with careful pruning to avoid dupl…

全排列 II

Generate all unique permutations of an array containing duplicates using backtracking and pruning to avoid repeated sequ…

旋转图像

Rotate an n x n matrix 90 degrees clockwise in-place using array manipulation and mathematical indexing techniques effic…

字母异位词分组

Group the anagrams in a list of strings using efficient hash table-based methods, focusing on array scanning.

N 皇后

Solve the N-Queens problem using backtracking with pruning, exploring all valid board placements while avoiding conflict…

最大子数组和

Maximum Subarray is a classic state transition dynamic programming problem about deciding whether to extend or restart a…

螺旋矩阵

Given an m x n matrix, return all elements in spiral order starting from the top-left corner.

跳跃游戏

Solve the Jump Game problem using state transition dynamic programming to determine if you can reach the last index of t…

合并区间

Merge Intervals requires sorting an array of interval pairs and combining overlaps efficiently using sequential comparis…

插入区间

Given a sorted array of non-overlapping intervals, insert a new interval and merge any overlapping intervals.

螺旋矩阵 II

Generate a spiral matrix of size n x n, filled with elements from 1 to n² in spiral order, for interview-focused solving…

不同路径 II

Calculate the number of unique paths from top-left to bottom-right in a grid with obstacles using dynamic programming st…

最小路径和

Compute the minimum sum from top-left to bottom-right in a grid using state transition dynamic programming efficiently.

加一

Given a number as an array of digits, increment it by one and return the updated array of digits.

文本左右对齐

Text Justification requires packing words into lines to match a specified width, ensuring even distribution of spaces.

矩阵置零

Modify the matrix in place by setting rows and columns to zero when an element is zero.

搜索二维矩阵

Search a 2D matrix efficiently using binary search over its linearized index, ensuring correctness in row-major sorted a…

颜色分类

Sort Colors requires in-place reordering of an array using a two-pointer scanning strategy to group 0s, 1s, and 2s effic…

子集

Generate all subsets of a set of unique integers using backtracking with pruning to avoid duplicates.

单词搜索

Solve Word Search with backtracking by exploring adjacent cells to match a target word in a grid.

删除有序数组中的重复项 II

Solve the problem of removing duplicates from a sorted array in-place, ensuring each element appears at most twice, usin…

搜索旋转排序数组 II

Determine if a target exists in a rotated sorted array that may contain duplicates using a binary search variation effic…

柱状图中最大的矩形

Find the maximal rectangular area in a histogram using stack-based state management for precise bar tracking and width c…

最大矩形

Compute the largest rectangle of 1's in a binary matrix using dynamic programming and stack-based state transitions effi…

合并两个有序数组

Merge two sorted arrays into the first array in non-decreasing order, using a two-pointer approach.

子集 II

Subsets II problem asks to generate unique subsets from an array with possible duplicates using backtracking search with…

从前序与中序遍历序列构造二叉树

Construct a binary tree using preorder and inorder traversal arrays, leveraging array scanning and hash table lookups.

从中序与后序遍历序列构造二叉树

Reconstruct a binary tree from given inorder and postorder arrays using array scanning and hash lookup to optimize recur…

将有序数组转换为二叉搜索树

Pick the middle element as root at each step so the sorted array becomes a height-balanced BST with valid ordering.

杨辉三角

Generate the first numRows of Pascal's Triangle using dynamic programming with clear state transitions and array manipul…

杨辉三角 II

Compute the specific row of Pascal's Triangle using efficient state transition dynamic programming with array-based upda…

三角形最小路径和

Given a triangle, return the minimum path sum from top to bottom, moving to adjacent numbers in the row below.

买卖股票的最佳时机

Maximize stock profit by identifying the optimal buy and sell days using dynamic programming.

买卖股票的最佳时机 II

Maximize stock profit by using a greedy approach to buy and sell multiple times, with state transition dynamic programmi…

买卖股票的最佳时机 III

Determine the maximum profit from at most two stock transactions using state transition dynamic programming on price arr…

最长连续序列

Find the length of the longest consecutive elements sequence in an unsorted array using array scanning and hash lookup.

被围绕的区域

Transform the matrix in-place by marking regions surrounded by 'X' as 'X', while keeping border-adjacent 'O's intact.

加油站

The Gas Station problem requires finding the starting station index for a full circular trip with gas stations and costs…

分发糖果

The Candy problem is a greedy algorithm challenge where you need to minimize candy distribution while satisfying certain…

只出现一次的数字

Solve the Single Number problem using an efficient approach with constant space and linear time complexity.

只出现一次的数字 II

Find the single element in an array where every other element appears three times, using bit manipulation and constant s…

单词拆分

Determine if a string can be fully segmented into dictionary words using array scanning and hash-based lookups for effic…

单词拆分 II

Given a string and dictionary, return all possible sentences by adding spaces where each word is in the dictionary.

直线上最多的点数

Find the maximum number of points on a straight line in a 2D plane using array scanning and hash lookup.

逆波兰表达式求值

Compute the result of an arithmetic expression in Reverse Polish Notation using a stack to manage operands efficiently.

乘积最大子数组

Find the subarray with the largest product in an integer array using dynamic programming techniques.

寻找旋转排序数组中的最小值

Find the minimum element in a rotated sorted array using binary search to efficiently identify the point of rotation.

寻找旋转排序数组中的最小值 II

Find the minimum in a rotated sorted array with possible duplicates using binary search.

寻找峰值

Find Peak Element leverages binary search for efficiently locating a peak in an array, a problem commonly asked in techn…

最大间距

Find the largest difference between successive elements in a sorted array efficiently using linear time techniques and b…

两数之和 II - 输入有序数组

Solve the Two Sum II problem efficiently using binary search over a valid answer space in a sorted array.

多数元素

Find the majority element in an array, where the element appears more than n/2 times, using efficient algorithms.

地下城游戏

Calculate the minimum initial health the knight needs to survive the dungeon using state transition dynamic programming …

最大数

The problem asks to arrange integers to form the largest possible number, focusing on greedy algorithms and string handl…

买卖股票的最佳时机 IV

Determine the maximum profit from at most k stock transactions using state transition dynamic programming on an array of…

轮转数组

Rotate Array challenges you to shift elements right by k steps using precise two-pointer scanning and invariant tracking…

打家劫舍

Maximize the amount of money you can rob tonight without alerting the police by applying dynamic programming with state …

岛屿数量

Count the number of distinct islands in a binary grid using array traversal combined with depth-first search exploration…

计数质数

Count all prime numbers less than a given integer n using efficient array and math-based enumeration techniques.

长度最小的子数组

Find the minimal length of a subarray whose sum is greater than or equal to the target using efficient algorithms.

单词搜索 II

Solve the Word Search II problem using backtracking with pruning to find all words on a board of characters.

打家劫舍 II

Maximize your loot by robbing houses arranged in a circle without alerting the police using dynamic programming.

数组中的第K个最大元素

Find the kth largest element in an unsorted array using optimal approaches like Quickselect or heaps.

组合总和 III

Find all unique combinations of k numbers adding to n using efficient backtracking with pruning in arrays.

存在重复元素

Determine if an integer array contains any duplicate values by efficiently scanning with a hash lookup to ensure fast de…

天际线问题

The Skyline Problem requires calculating a city's silhouette using array manipulation and divide-and-conquer techniques …

存在重复元素 II

Check if any two equal numbers exist within k indices using array scanning and hash table lookup efficiently.

存在重复元素 III

The problem involves finding a pair of indices in an array where the index and value differences are within given limits…

最大正方形

Maximal Square is a matrix-based dynamic programming problem that focuses on finding the largest square filled with 1's.

汇总区间

Summary Ranges involves converting a sorted array of unique integers into a minimal list of range strings.

多数元素 II

Identify all elements in an integer array appearing more than ⌊ n/3 ⌋ times using efficient array scanning and hash coun…

除了自身以外数组的乘积

Solve the 'Product of Array Except Self' problem by calculating the product of all elements except self for each index e…

滑动窗口最大值

Solve the "Sliding Window Maximum" problem using efficient techniques like the sliding window, deque, and priority queue…

搜索二维矩阵 II

Efficiently search for a target in a 2D matrix using binary search and matrix properties.

只出现一次的数字 III

Find the two unique numbers in an array where all other numbers appear exactly twice using bit manipulation efficiently.

丢失的数字

Find the missing number in an array containing distinct numbers in the range [0, n].

H 指数

Determine a researcher's h-index by analyzing citations using array sorting and counting techniques efficiently and accu…

H 指数 II

Compute a researcher's H-Index from a sorted citation array using binary search over the valid answer space efficiently.

移动零

Move all zeros in an array to the end while preserving the order of non-zero elements using efficient in-place operation…

窥视迭代器

Design an iterator with peek functionality, adding to the standard next and hasNext operations for efficient element acc…

寻找重复数

The problem involves finding the duplicate number in an array of integers, using a binary search approach over the valid…

生命游戏

Solve the Game of Life by updating each cell based on its eight neighbors using Array and Matrix simulation patterns eff…

最长递增子序列

Solve the Longest Increasing Subsequence problem using dynamic programming and binary search to efficiently find the sub…

区域和检索 - 数组不可变

The Range Sum Query - Immutable problem involves implementing a data structure to handle range sum queries efficiently.

二维区域和检索 - 矩阵不可变

Design a 2D matrix class that efficiently handles sum queries with O(1) time complexity using a prefix sum approach.

区域和检索 - 数组可修改

Implement a mutable range sum query using efficient design patterns to handle multiple updates and range sum queries.

买卖股票的最佳时机含冷冻期

Maximize stock profit with cooldown restrictions using state transition dynamic programming to track buy, sell, and cool…

戳气球

Burst Balloons is a hard dynamic programming problem requiring careful state transitions to maximize coins collected eff…

超级丑数

Compute the nth super ugly number efficiently using dynamic programming with state transitions based on the given prime …

计算右侧小于当前元素的个数

Solve the Count of Smaller Numbers After Self problem using binary search and optimized algorithms.

最大单词长度乘积

The problem requires finding the maximum product of lengths of two words from an array, where the words don't share comm…

拼接最大数

Create Maximum Number involves merging digits from two arrays while preserving order, maximizing the resulting number.

零钱兑换

Find the minimum number of coins needed to reach a target amount using dynamic programming state transitions efficiently…

摆动排序 II

Rearrange an array in a way that every odd-indexed element is greater than its adjacent even-indexed elements.

区间和的个数

Count the number of subarray sums within a given inclusive range using optimized divide-and-conquer techniques efficient…

矩阵中的最长递增路径

Find the length of the longest increasing path in a matrix with given movement constraints using graph techniques.

按要求补齐数组

Patching Array requires adding the minimum numbers to cover all sums from 1 to n using greedy choices and invariant chec…

递增的三元子序列

Identify if an array contains a strictly increasing triplet by maintaining a running minimal and middle value efficientl…

路径交叉

Determine if a path defined by sequential distances on a 2D plane crosses itself using array and math reasoning.

回文对

Find all pairs of words in a list that form palindromes when concatenated using efficient scanning and hash mapping.

前 K 个高频元素

Find the k most frequent elements from an array using efficient algorithms like hashing and sorting.

两个数组的交集

Find the intersection of two arrays while ensuring unique elements using efficient array scanning and hash lookups.

两个数组的交集 II

Find the intersection of two arrays, accounting for multiple occurrences of the same number.

俄罗斯套娃信封问题

Russian Doll Envelopes is a dynamic programming problem that involves finding the longest chain of envelopes that can be…

矩形区域不超过 K 的最大数值和

Solve the "Max Sum of Rectangle No Larger Than K" problem using binary search over the valid sum space to optimize space…

最大整除子集

Find the largest subset of distinct positive integers where every pair satisfies divisibility using state transition dyn…

查找和最小的 K 对数字

Find K Pairs with Smallest Sums combines arrays and heap usage to select the smallest sum pairs efficiently.

摆动序列

Find the longest wiggle subsequence in an integer array using state transition dynamic programming with greedy optimizat…

组合总和 Ⅳ

Combination Sum IV asks to find the number of combinations that sum to a given target using elements from an array.

有序矩阵中第 K 小的元素

Find the kth smallest element in a sorted n x n matrix using efficient binary search or heap strategies for optimized me…

O(1) 时间插入、删除和获取随机元素

Implement a data structure supporting insert, delete, and getRandom in average O(1) using array plus hash mapping.

O(1) 时间插入、删除和获取随机元素 - 允许重复

This problem challenges you to design a data structure that supports insertion, removal, and random access with O(1) tim…

打乱数组

Shuffle an Array requires designing a class to randomly permute an integer array while ensuring all permutations are equ…

完美矩形

Determine if given axis-aligned rectangles form a perfect cover using array scanning and hash-based corner counting tech…

UTF-8 编码验证

Determine if an integer array represents valid UTF-8 encoding based on its byte sequences using bit manipulation.

旋转函数

Maximize the rotation function by rotating the array and calculating the weighted sum for all rotations.

除法求值

Compute the results of division queries from given equations using graph traversal and depth-first search efficiently.

青蛙过河

Determine if a frog can cross a river using jumps constrained by previous step sizes in a dynamic programming state tran…

根据身高重建队列

Reconstruct a queue based on the given heights and the number of taller people in front, using sorting and binary indexe…

接雨水 II

Solve Trapping Rain Water II using breadth-first search and priority queues for efficient water trapping in a matrix.

分割数组的最大值

Solve the 'Split Array Largest Sum' problem by minimizing the largest sum across k subarrays using dynamic programming a…

等差数列划分

Count the number of arithmetic subarrays in a given integer array using dynamic programming.

第三大的数

Find the third distinct maximum number in an array using array traversal and sorting techniques, handling duplicates car…

分割等和子集

Determine if an array can be partitioned into two subsets with equal sum using dynamic programming techniques.

太平洋大西洋水流问题

Find all cells on an island where water can flow to both the Pacific and Atlantic oceans using DFS or BFS.

棋盘上的战舰

Count the number of non-overlapping battleships on a 2D board using array traversal and depth-first search patterns effi…

数组中两个数的最大异或值

Find the maximum XOR of two numbers in an integer array using efficient bit manipulation techniques.

建立四叉树

Construct a Quad-Tree from a binary matrix by recursively subdividing regions and tracking uniform states efficiently.

无重叠区间

Determine the minimum number of intervals to remove from a list to ensure no intervals overlap using dynamic programming…

数组中重复的数据

Find all integers that appear twice in an array with O(n) time and constant space complexity.

等差数列划分 II - 子序列

Count all arithmetic subsequences in an array using dynamic programming with precise state transitions for correctness.

回旋镖的数量

Compute all valid boomerang tuples in a point set using array scanning with hash maps to track distances efficiently.

找到所有数组中消失的数字

Identify all missing numbers in an array using efficient scanning and hash-based lookup for optimal performance.

用最少数量的箭引爆气球

Find the minimum number of arrows needed to burst all balloons by considering greedy choice and invariant validation.

最小操作次数使数组元素相等

Compute the fewest steps to make all elements equal by incrementing n-1 array items, applying array and math reasoning.

四数相加 II

Count all quadruples from four integer arrays that sum to zero using efficient array scanning and hash table lookups.

分发饼干

Maximize content children by assigning at most one cookie per child using two-pointer scanning and greedy sorting techni…

132 模式

Identify whether a given integer array contains a 132 pattern subsequence using efficient stack and search techniques.

环形数组是否存在循环

Detect whether a circular array contains a loop of consistent direction using efficient array scanning and hash lookup t…

最小操作次数使数组元素相等 II

Find the minimum moves to equalize all array elements using increments or decrements with array and math techniques.

岛屿的周长

Determine the perimeter of an island in a grid of land and water cells using DFS or BFS.

连接词

Find concatenated words by using dynamic programming and depth-first search to identify valid words made of other words …

火柴拼正方形

The problem asks to determine if we can use matchsticks to form a square, exploring dynamic programming and backtracking…

一和零

Solve the Ones and Zeroes problem using dynamic programming with state transition, focusing on array and string manipula…

供暖器

Determine the minimum heater radius to cover all houses using a binary search over potential radius values efficiently.

汉明距离总和

Calculate the total Hamming distance between all pairs in an integer array using efficient bit manipulation techniques.

滑动窗口中位数

Compute the median for each sliding window of size k in an array using efficient array scanning and hash lookup techniqu…

最大连续 1 的个数

Find the maximum sequence of consecutive 1s in a binary array using an efficient array-driven scanning approach.

预测赢家

Predict the Winner involves two players taking turns to maximize their score by picking from either end of an array, opt…

非递减子序列

Return all possible non-decreasing subsequences with at least two elements from the input array, nums.

翻转对

Count the number of reverse pairs in a given integer array using efficient algorithms like binary search and merge sort.

目标和

Target Sum requires counting all expressions from nums using '+' or '-' that evaluate exactly to the given target intege…

提莫攻击

Compute the total poisoned time Ashe experiences from Teemo's attacks using an array-based simulation approach efficient…

下一个更大元素 I

Find the next greater element for each number in nums1 from the nums2 array using an optimized approach.

非重叠矩形中的随机点

Design an algorithm to pick random points within non-overlapping rectangles using binary search and reservoir sampling.

对角线遍历

Traverse a matrix diagonally and return all elements in the specific zig-zag order required by the problem pattern.

键盘行

Identify all words from a list that can be typed using letters from only one row of a standard American keyboard.

IPO

Maximize total capital by selecting up to k projects, based on initial capital and project profits using a greedy strate…

下一个更大元素 II

Solve the Next Greater Element II problem by using a stack-based state management approach for circular arrays.

相对名次

Solve Relative Ranks by sorting scores with original indices, then writing medal labels or numeric places back in answer…

超级洗衣机

Calculate the minimum moves to balance dresses across washing machines using a greedy strategy and invariant validation …

零钱兑换 II

Calculate the number of unique coin combinations to reach a target amount using state transition dynamic programming eff…

最长特殊序列 II

Find the longest string in an array that is not a subsequence of any other string, using array scanning and hash checks …

连续的子数组和

Identify if any continuous subarray sums to a multiple of k using prefix sums and hash table tracking efficiently.

通过删除字母匹配到字典里最长单词

Find the longest word in the dictionary that can be formed by deleting characters from a string, using two-pointer scann…

连续数组

Find the maximum length contiguous subarray with equal numbers of 0s and 1s using array scanning and hash lookup efficie…

优美的排列

The Beautiful Arrangement problem asks for the number of valid permutations of n integers satisfying specific divisibili…

按权重随机选择

Random Pick with Weight requires implementing a probabilistic index picker using prefix sums and binary search efficient…

扫雷游戏

Solve the Minesweeper game by updating revealed squares and handling clicks with Depth-First Search and Array manipulati…

数组中的 k-diff 数对

Solve K-diff Pairs in an Array by counting unique differences with a hash map or sorted two-pointer sweep.

最小时间差

Calculate the smallest time difference between clock points using array manipulation and mathematical conversions effici…

有序数组中的单一元素

Find the single non-duplicate element in a sorted array where every other element appears exactly twice.

01 矩阵

The '01 Matrix' problem challenges you to find the nearest zero for each cell in a binary matrix using dynamic programmi…

移除盒子

Maximize points by strategically removing contiguous same-colored boxes using state transition dynamic programming and m…

最优除法

Maximize the value of an expression by optimally placing parentheses for division operations.

砖墙

Solve the Brick Wall problem using array scanning and hash lookups to minimize crossed bricks from a vertical line.

和为 K 的子数组

Count the total number of contiguous subarrays in an integer array that sum exactly to a target value k using optimized …

数组拆分

Maximize the sum of minimums of n pairs in a 2n integer array using a greedy pairing strategy efficiently.

数组嵌套

Find the longest nested set in a permutation array using a depth-first traversal, handling cycles efficiently for medium…

重塑矩阵

Reshape the Matrix involves transforming a 2D matrix into a new matrix with the same elements in row-major order, follow…

分糖果

Maximize the number of different candies Alice can eat given a set of candies and constraints on quantity.

最短无序连续子数组

Find the shortest unsorted continuous subarray that, if sorted, would sort the entire array.

安装栅栏

Find the perimeter fence of a garden by determining the outermost trees in a set of given tree coordinates.

最长和谐子序列

Find the length of the longest harmonious subsequence in an integer array using array scanning and hash-based frequency …

区间加法 II

Range Addition II requires counting maximum values in a matrix after incremental operations using array and math reasoni…

两个列表的最小索引总和

Find the common strings between two lists with the smallest index sum in this easy problem involving array scanning and …

种花问题

Determine if n new flowers can be planted in a flowerbed, ensuring no adjacent flowers using a greedy approach.

在系统中查找重复文件

Find and return duplicate files in the file system, grouping them by their paths and contents using an array scanning ap…

有效三角形的个数

Count all triplets in an integer array that satisfy the triangle inequality to form valid triangles efficiently using so…

任务调度器

Task Scheduler is solved by counting task frequencies and computing how cooldown gaps force idle slots around the most f…

设计循环队列

Design a circular queue that allows efficient FIFO operations using linked-list pointer manipulation to optimize space u…

数组列表中的最大距离

Maximum Distance in Arrays uses a greedy running minimum and maximum from previous arrays to validate cross array distan…

三个数的最大乘积

Find three numbers in an array whose product is the largest using sorting and careful handling of negative values.

课程表 III

Solve the 'Course Schedule III' problem with a greedy approach involving course selection and validation of constraints.

最小区间

Find the minimal range covering at least one number from each of k sorted lists using array scanning and hash lookup eff…

函数的独占时间

Solve the 'Exclusive Time of Functions' problem using stack-based state management for accurate function execution time …

大礼包

Minimize the cost of purchasing items using available special offers with state transition dynamic programming.

设计循环双端队列

Design and implement a circular deque using linked-list pointer manipulation, ensuring efficient insertion and deletion …

子数组最大平均数 I

Find the maximum average of any contiguous subarray of length k in a given integer array using a sliding window approach…

错误的集合

Identify the duplicated and missing numbers in an integer array using array scanning combined with hash table lookup eff…

最长数对链

Determine the maximum length of a chain formed by pairs using dynamic programming and greedy sorting techniques efficien…

单词替换

Replace words in a sentence using the shortest root from a dictionary, applying efficient array scanning and hash lookup…

最大二叉树

Construct a maximum binary tree by recursively selecting the largest element and dividing the array into left and right …

找到 K 个最接近的元素

Identify the k integers closest to a target x in a sorted array using binary search and two-pointer strategies efficient…

分割数组为连续子序列

Verify if it's possible to split a sorted array into consecutive subsequences of length 3 or more.

图片平滑器

Apply a 3x3 smoothing filter to a matrix, rounding down each cell average including surrounding neighbors for accurate r…

非递减数列

Check if an array can become non-decreasing by modifying at most one element using an array-driven solution strategy.

优美的排列 II

Construct a beautiful arrangement of integers from 1 to n with k distinct integers, optimizing for time and space effici…

最长递增子序列的个数

This problem challenges you to find the number of longest increasing subsequences in a given array of integers.

最长连续递增序列

Find the length of the longest continuous increasing subsequence in an unsorted integer array using an array-driven solu…

为高尔夫比赛砍树

Determine the minimum steps to cut all trees in a forest matrix in ascending height order using BFS traversal and priori…

24 点游戏

Solve the 24 Game by arranging four card numbers using arithmetic operators and parentheses to reach exactly 24 efficien…

棒球比赛

Simulate baseball score operations using a stack-based approach to compute the final score after all operations.

三个无重叠子数组的最大和

Maximize the sum of three non-overlapping subarrays with length k in an integer array using dynamic programming.

员工的重要性

Calculate an employee's total importance including all direct and indirect subordinates using array scanning and hash lo…

贴纸拼词

Determine the minimum number of stickers needed to spell a target word using array scanning and hash lookups for efficie…

前K个高频单词

Solve Top K Frequent Words by counting each word, then ordering ties alphabetically so frequency wins before lexicograph…

岛屿的最大面积

Find the largest connected land area in a binary grid using array traversal and depth-first search efficiently.

数组的度

Find the shortest subarray with the same degree as the given array using efficient array scanning and hash lookups.

划分为k个相等的子集

Determine if an integer array can be partitioned into k subsets where each subset sums to the same value using DP and ba…

掉落的方块

Solve Falling Squares by efficiently computing maximum stack heights using arrays with segment tree optimization techniq…

二分查找

Solve the Binary Search problem by finding the index of a target value in a sorted array with O(log n) complexity.

设计哈希集合

Implement a custom HashSet without built-in libraries using array scanning and hash lookup for efficient membership chec…

设计哈希映射

Implement a custom HashMap from scratch using array scanning and hash lookup without built-in libraries for efficient ke…

黑名单中的随机数

Random Pick with Blacklist requires designing a method to uniformly pick integers while excluding blacklisted values eff…

乘积小于 K 的子数组

Count subarrays with a product strictly less than a given value k using efficient algorithms like binary search and slid…

买卖股票的最佳时机含手续费

Maximize stock trading profits accounting for per-transaction fees using state transition dynamic programming and greedy…

1 比特与 2 比特字符

Determine whether the last character in a binary array represents a one-bit character or a two-bit character.

最长重复子数组

Find the maximum length of a subarray that appears in both given integer arrays using dynamic programming.

找出第 K 小的数对距离

Solve Find K-th Smallest Pair Distance by sorting nums, then binary searching the distance and counting valid pairs with…

词典中最长的单词

Find the longest word in a dictionary that can be built one character at a time from other words in the dictionary.

账户合并

Merge accounts by connecting emails and returning each user's sorted email list using array scanning and hash lookup eff…

删除注释

Remove comments from a given C++ program source array, handling line and block comments.

寻找数组的中心下标

Find the pivot index in an array where the sums of elements on both sides are equal using array and prefix sum technique…

我的日程安排表 I

Implement a calendar supporting non-overlapping event bookings using binary search for efficient insertion and conflict …

我的日程安排表 II

Implement a calendar that allows double bookings but prevents triple bookings, managing overlapping intervals efficientl…

图像渲染

Flood Fill is an array and DFS problem where you change connected pixels to a target color efficiently using recursion o…

小行星碰撞

Determine the final positions of moving asteroids using a stack-based simulation for efficient collision resolution in l…

每日温度

In the Daily Temperatures problem, you need to find out how many days to wait for a warmer temperature based on given da…

删除并获得点数

Maximize points by deleting numbers from an array while removing all adjacent values, using dynamic programming efficien…

摘樱桃

Maximize cherries collected on a grid, employing state transition dynamic programming with careful navigation across obs…

寻找比目标字母大的最小字母

Locate the smallest character in a sorted array that is strictly greater than a given target using efficient binary sear…

前缀和后缀搜索

Design a dictionary to search words by both prefix and suffix using a Trie structure and hash lookups.

使用最小花费爬楼梯

Compute the minimum cost to reach the top of a staircase using dynamic programming and step-by-step state transitions ef…

至少是其他数字两倍的最大数

Determine if the largest number in the array is at least twice as large as every other element, and return its index or …

最短补全词

Find the shortest word that completes the license plate by matching all required letters, considering frequency and case…

隔离病毒

Contain Virus involves using array-based Depth-First Search to contain viral spread by building walls around infected re…

打开转盘锁

Solve the Open the Lock problem using array scanning plus hash lookup to efficiently find the shortest unlock sequence.

设置交集大小至少为2

Solve the Set Intersection Size At Least Two problem using a greedy approach and invariant validation.

最大加号标志

Find the largest axis-aligned plus sign in a binary grid with some mines using dynamic programming.

托普利茨矩阵

Determine if a given matrix is a Toeplitz matrix by checking diagonal consistency.

最多能完成排序的块 II

Determine the maximum number of chunks you can split an array into so that sorting each chunk results in a fully sorted …

最多能完成排序的块

The Max Chunks To Make Sorted problem requires you to split an array into the maximum number of chunks that can be sorte…

滑动谜题

Determine the minimum moves to solve a 2x3 sliding puzzle using BFS and state transition dynamic programming techniques …

全局倒置与局部倒置

Determine if every global inversion in a permutation array is also a local inversion using array and math logic efficien…

水位上升的泳池中游泳

Solve the problem of swimming through a grid of rising water with a binary search on the valid answer space.

森林中的兔子

Solve Rabbits in Forest by grouping equal answers and rounding each group into the smallest valid color-class size.

变为棋盘

Determine the minimum swaps of rows or columns to convert an n x n binary board into a valid chessboard configuration.

第 K 个最小的质数分数

Find the k-th smallest fraction from a sorted array of unique primes using a binary search over the answer space.

逃脱阻碍者

Escape The Ghosts tests your ability to analyze movements in an infinite grid while racing against ghost positions using…

匹配子序列的单词数

Given a string s and a list of words, count how many words are subsequences of s using efficient array scanning and hash…

有效的井字游戏

Verify if a given Tic-Tac-Toe board can represent a valid game state during a valid sequence of moves.

区间子数组个数

Count the number of contiguous subarrays with a bounded maximum value using a two-pointer approach.

得分最高的最小轮调

Find the smallest rotation index with the highest score using array and prefix sum techniques.

使序列递增的最小交换次数

This problem involves finding the minimum number of swaps needed to make two sequences strictly increasing using dynamic…

打砖块

Bricks Falling When Hit challenges your ability to simulate brick falls after sequential erasures using Union Find.

唯一摩尔斯密码词

Determine how many unique Morse code transformations can be generated from a list of words using a hash table and array …

数组的均值分割

Determine whether an integer array can be partitioned into two non-empty subarrays with the same average using dynamic p…

写字符串需要的行数

Calculate how many lines are needed to write a string given individual letter widths, constrained to 100 pixels per line…

保持城市天际线

Maximize building heights in a city grid without changing the skyline, using greedy selection constrained by row and col…

情感丰富的文字

Expressive Words challenges you to determine if a word can be transformed into a given string by extending groups of rep…

黑板异或游戏

The Chalkboard XOR Game is a game theory problem involving array manipulation and bitwise XOR, where players alternate e…

子域名访问计数

The Subdomain Visit Count problem requires counting the visits to all subdomains of a given domain from a list of count-…

最大三角形面积

Find the area of the largest triangle formed by three distinct points on a 2D plane.

最大平均值和的分组

Maximize the sum of averages by partitioning an integer array into at most k contiguous subarrays using dynamic programm…

公交路线

Bus Routes is solved by BFS over buses and stops, using stop-to-route hashing to avoid expensive repeated route scans.

链表组件

Count the number of connected components in a linked list subset using array scanning and hash table lookups efficiently…

最常见的单词

Find the most frequent non-banned word in a paragraph, excluding punctuation, using an efficient array scan and hash tab…

单词的压缩编码

Find the minimum length of a reference string encoding an array of words using array scanning and hash lookup efficientl…

字符的最短距离

Compute the minimum distance from each character in a string to a target character using efficient scanning techniques.

翻转卡片游戏

The Card Flipping Game problem asks for the smallest integer that can be facing down but not up after flipping cards.

带因子的二叉树

Given an array of integers, find how many binary trees can be formed such that non-leaf nodes' values are the product of…

适龄的朋友

The Friends Of Appropriate Ages problem involves counting valid friend requests between people based on their ages with …

安排工作以达到最大收益

Assign workers to jobs maximizing total profit using difficulty, profit, and worker arrays efficiently with binary searc…

最大人工岛

Calculate the largest island size by converting at most one zero in a binary grid using array and DFS techniques efficie…

翻转图像

Flip each row of a binary matrix horizontally and invert its values efficiently using a two-pointer scanning approach.

字符串中的查找与替换

This problem challenges you to perform multiple string replacements at specific indices using a pattern involving array …

图像重叠

Image Overlap requires calculating the overlap between two binary matrices by translating one image over the other.

相似字符串组

Determine the number of connected groups of similar strings by swapping at most two letters using array scanning and has…

矩阵中的幻方

Scan every 3x3 window, reject invalid digits fast, then verify row, column, and diagonal sums for Magic Squares In Grid.

猜猜这个单词

Master the Guess the Word problem by applying array manipulation, match-counting math, and strategic interactive guessin…

数组中的最长山脉

Find the length of the longest subarray forming a mountain pattern using state transitions and two-pointer logic efficie…

一手顺子

Check if a hand of cards can be rearranged into groups of consecutive values.

字母移位

Given a string and a shift array, shift the first i+1 letters of the string as specified in the array.

到最近的人的最大距离

Determine the seat placement that maximizes distance to the nearest person using a linear array scan strategy efficientl…

矩形面积 II

The problem involves calculating the total area covered by multiple rectangles, ensuring overlap is counted only once.

喧闹和富有

Determine the quietest person richer than each individual using graph indegree analysis and topological ordering techniq…

山脉数组的峰顶索引

Find the peak index in a mountain array using binary search for efficient O(log n) time complexity.

车队

The Car Fleet problem asks how many car fleets will reach a target given their starting positions and speeds, considerin…

雇佣 K 名工人的最低成本

Find the minimum cost to hire exactly k workers based on quality and wage expectations in this challenging greedy proble…

柠檬水找零

Determine if you can provide exact change to every customer at a lemonade stand using greedy bill management techniques.

翻转矩阵后的得分

Maximize the score of a binary matrix by flipping rows and columns using a greedy approach and validation of invariants.

和至少为 K 的最短子数组

Find the shortest subarray with a sum of at least k using binary search and sliding window techniques.

获取所有钥匙的最短路径

Find the minimum steps to collect all keys in a grid using BFS and bitmasking, handling locks efficiently.

转置矩阵

Transpose Matrix problem requires flipping a matrix's rows and columns to return the transposed version.

优势洗牌

Maximize the advantage of nums1 over nums2 using a two-pointer greedy strategy, carefully tracking which elements beat o…

最低加油次数

Determine the minimum number of refueling stops needed to reach a target using dynamic programming and greedy strategies…

最长的斐波那契子序列的长度

Find the length of the longest Fibonacci-like subsequence from a strictly increasing array of integers.

模拟行走机器人

The Walking Robot Simulation problem involves moving a robot in an infinite grid and calculating its furthest distance f…

爱吃香蕉的珂珂

Koko Eating Bananas challenges you to find the minimum eating speed to finish piles of bananas in a given time using bin…

石子游戏

Stone Game is a dynamic programming problem where players alternate taking stones from piles to maximize their score.

盈利计划

Given a group of members and a list of crimes, count the profitable schemes that meet the profit and group constraints.

救生艇

Find the minimum number of boats required to save all people, using a two-pointer approach for efficient pairing.

三维形体投影面积

Calculate the projection area of a 3D shape defined by a grid of towers with varying heights.

螺旋矩阵 III

Solve the Spiral Matrix III problem by simulating the movement across a matrix with specific constraints on direction an…

公平的糖果交换

Determine which single candy box Alice and Bob should swap to equalize their total candies using array scanning and hash…

根据前序和后序遍历构造二叉树

Reconstruct a binary tree from preorder and postorder traversals using array scanning and hash lookup.

查找和替换模式

Identify all words matching a given pattern by checking consistent letter mappings using hash tables and array scanning …

子序列宽度之和

Calculate the sum of widths for all subsequences in an integer array using sorting and combinatorial math efficiently.

三维形体的表面积

Solve the Surface Area of 3D Shapes problem using array manipulation and mathematical formulas to calculate surface area…

特殊等价字符串组

Determine the number of special-equivalent string groups using character swaps at even or odd indices efficiently.

单调数列

Determine if an integer array is entirely monotone increasing or decreasing using a clear array-driven approach.

子数组按位或操作

Compute the number of unique bitwise OR values from all non-empty subarrays using dynamic state transitions efficiently.

RLE 迭代器

Design an efficient iterator for a run-length encoded array, handling large counts and sequential access correctly every…

最大为 N 的数字组合

The 'Numbers At Most N Given Digit Set' problem requires calculating how many numbers can be formed using a given digit …

水果成篮

The Fruit Into Baskets problem requires finding the maximum number of fruits you can pick from a row of trees under spec…

按奇偶排序数组

Reorder an integer array so all even numbers come before odd numbers using a precise two-pointer scanning method.

子数组的最小值之和

Calculate the sum of minimum values across all subarrays of a given array modulo 10^9 + 7.

最小差值 I

Find the smallest score of an array after applying an operation to each element within a given range.

蛇梯棋

Solve the Snakes and Ladders problem using a BFS strategy to efficiently navigate the board and reach the final square.

最小差值 II

Determine the minimum possible difference between the largest and smallest numbers after adjusting each by plus or minus…

在线选举

Solve the Online Election problem by implementing a class that tracks votes and queries the leading candidate at any giv…

排序数组

Sort an array using an optimal algorithm, focusing on time and space complexity considerations.

卡牌分组

Solve the problem of determining if a deck can be partitioned into groups with equal occurrences of card values.

分割数组

Partition the array into two subarrays such that the left contains the smallest possible elements and the right contains…

单词子集

Word Subsets is solved by merging words2 into one max-frequency requirement, then scanning words1 against that fixed let…

环形子数组的最大和

Find the maximum sum of a circular subarray using state transition dynamic programming, optimizing for wraparound cases …

按奇偶排序数组 II

Sort an array where even numbers appear at even indices and odd numbers appear at odd indices using two-pointer scanning…

三数之和的多种可能

Count all unique triplets in an integer array whose sum equals the target, handling multiplicity efficiently using hashi…

尽量减少恶意软件的传播

Identify which single infected node to remove to minimize total malware spread in a connected network graph efficiently.

三等分

Divide a binary array into three contiguous parts such that each part represents the same integer value in binary, using…

尽量减少恶意软件的传播 II

Minimize Malware Spread II asks to minimize the spread of malware in a network of nodes by removing one infected node.

独特的电子邮件地址

Identify the count of unique email addresses by normalizing local names and using hash-based lookups efficiently.

和相同的二元子数组

Count all contiguous subarrays in a binary array whose elements sum exactly to a given goal using prefix sums efficientl…

下降路径最小和

Minimum Falling Path Sum is a matrix dynamic programming problem where each cell depends on three reachable cells above …

漂亮数组

Beautiful Array builds a valid permutation by recursively separating odd and even positions so no middle-average triple …

最短的桥

Find the minimum flips to connect two separate islands in a binary matrix using Array and DFS techniques efficiently.

重新排列日志文件

Reorder Data in Log Files requires sorting letter-logs lexicographically while keeping digit-logs in original order for …

最小面积矩形

Find the minimum area of a rectangle formed by given points on a 2D plane with sides parallel to axes.

有效的山脉数组

The 'Valid Mountain Array' problem requires determining if an array meets the conditions of a valid mountain array using…

增减字符串匹配

Reconstruct a permutation from a DI string using two-pointer scanning, carefully tracking the increasing and decreasing …

最短超级串

This problem requires constructing the shortest string containing all input words using state transition dynamic program…

删列造序

The 'Delete Columns to Make Sorted' problem asks to remove unsorted columns from a string array, ensuring all columns ar…

使数组唯一的最小增量

This problem challenges you to find the minimum moves to make all elements in an array unique by incrementing elements.

验证栈序列

Determine if a sequence of push and pop operations can produce the given popped array using a stack-based state approach…

令牌放置

Maximize your score in the Bag of Tokens problem by strategically playing tokens with two-pointer scanning and greedy te…

给定数字能组成的最大时间

Given four digits, determine the latest valid 24-hour time possible using each digit exactly once with backtracking.

按递增顺序显示卡牌

Determine the initial deck order to reveal cards in strictly increasing order using queue-driven simulation logic.

按公因数计算最大组件大小

Find the largest connected component in an array where edges exist between numbers sharing a common factor greater than …

验证外星语词典

Verify if a sequence of words is sorted according to an alien language's custom alphabet order using array scanning and …

二倍数对数组

Given an array of even length, check if it can be reordered to satisfy a specific doubling condition.

删列造序 II

Solve the "Delete Columns to Make Sorted II" problem by applying greedy choices and invariant validation to string array…

最高的广告牌

Solve the Tallest Billboard problem by using dynamic programming to find the maximum equal height for two disjoint rod s…

N 天后的牢房

Determine the state of 8 prison cells after N days using array scanning and cycle detection for repeated patterns effici…

由斜杠划分区域

Determine the number of regions in a grid divided by slashes using array scanning and union-find techniques efficiently.

删列造序 III

The problem requires minimizing deletions to ensure all strings are lexicographically sorted. Use dynamic programming fo…

在长度 2N 的数组中找出重复 N 次的元素

Find the element that is repeated exactly N times in a 2N-sized array using array scanning and hash lookups.

最大宽度坡

Find the maximum width of a ramp where nums[i] <= nums[j] for i < j using a two-pointer approach.

最小面积矩形 II

Find the minimum area rectangle from given points in the X-Y plane, with sides not necessarily parallel to the axes.

元音拼写检查器

Implement a spellchecker that matches queries to a wordlist using exact, case-insensitive, and vowel-error rules efficie…

煎饼排序

Sort an array using pancake flips, leveraging two-pointer scanning and invariant tracking to iteratively position the la…

最接近原点的 K 个点

Find the k closest points to the origin in a 2D plane using array operations and Euclidean distance calculations efficie…

和可被 K 整除的子数组

Count the number of subarrays whose sum is divisible by a given integer k using array scanning and hash lookup.

奇偶跳

Determine the number of valid starting indices in an array where you can reach the end with alternating odd and even jum…

三角形的最大周长

Given an integer array, find the largest perimeter of a triangle formed from three of these lengths.

有序数组的平方

The problem involves squaring elements of a sorted array and returning the squares in non-decreasing order.

最长湍流子数组

Find the length of the longest subarray where element comparisons alternate, using state transition dynamic programming …

不同路径 III

Solve the Unique Paths III problem using backtracking search with pruning to count 4-directional paths covering all empt…

按位与为零的三元组

Count all index triples in an array where the bitwise AND of their elements equals zero using efficient bit manipulation…

最低票价

Solve the Minimum Cost For Tickets problem using state transition dynamic programming for optimal travel ticket purchase…

查询后的偶数和

Efficiently update an integer array based on queries and compute the sum of even numbers after each modification using s…

区间列表的交集

This problem requires finding the intersection of two lists of intervals using a two-pointer technique with invariant tr…

数组形式的整数加法

Compute the sum of an integer and a number represented as an array, efficiently handling digit carries and array travers…

等式方程的可满足性

Determine if it's possible to assign values to variables such that all equations are satisfied based on equality and ine…

K 个不同整数的子数组

Find subarrays with exactly k distinct integers in an integer array using sliding window and hash lookup techniques.

腐烂的橘子

Given a grid with fresh and rotten oranges, return the minimum time for all oranges to rot or -1 if impossible.

K 连续位的最小翻转次数

Determine the minimum number of k-length consecutive bit flips needed to convert all zeros to ones in a binary array eff…

平方数组的数目

Count the number of squareful arrays from the given list of integers by checking adjacent pairs' sums for perfect square…

找到小镇的法官

Find the Town Judge is an easy LeetCode problem that challenges you to identify a town judge from trust relationships us…

可以被一步捕获的棋子数

This problem involves finding the number of pawns a rook can capture on a chessboard, considering obstacles like bishops…

合并石头的最低成本

Minimize the cost to merge stones with k consecutive piles using dynamic programming to achieve the optimal solution.

网格照明

Grid Illumination uses an array scanning approach with hash lookups to check illuminated cells in a large grid based on …

查找共用字符

Return an array of common characters from all strings in the given list of words, including duplicates.

最大连续1的个数 III

Find the longest consecutive ones in a binary array by optimally flipping at most k zeros using sliding window technique…

K 次取反后最大化的数组和

Maximize the sum of an integer array after exactly k negations using a greedy approach and invariant tracking for optima…

行相等的最少多米诺旋转

Minimize domino rotations to make either row identical in the problem of Minimum Domino Rotations For Equal Row.

前序遍历构造二叉搜索树

Construct a binary search tree directly from a preorder traversal array using stack-based state tracking efficiently.

总持续时间可被 60 整除的歌曲

Calculate the number of song pairs whose total durations sum to a multiple of 60 using array scanning and hash lookups.

在 D 天内送达包裹的能力

Find the minimum ship capacity needed to ship all packages within D days, ensuring the cargo is shipped in the given ord…

将数组分成和相等的三个部分

Determine if an array can be partitioned into three non-empty parts with equal sum using greedy choice and validation.

最佳观光组合

Compute the maximum sightseeing score efficiently using state transition dynamic programming and single-pass array itera…

可被 5 整除的二进制前缀

Determine which binary prefixes of a given array are divisible by 5 using bit manipulation for efficient checks.

链表中的下一个更大节点

Find the next greater value for each node in a linked list using monotonic stack techniques for efficient traversal.

飞地的数量

This problem involves finding the number of land cells that cannot reach the boundary in a grid using DFS and array mani…

驼峰式匹配

Camelcase Matching is a medium difficulty problem where you match queries to a given pattern by inserting lowercase lett…

视频拼接

Solve the "Video Stitching" problem using state transition dynamic programming to cover a sporting event with minimum cl…

最长等差数列

Find the length of the longest arithmetic subsequence in a given integer array using scanning and hash-based lookup.

两地调度

Two City Scheduling requires selecting optimal city assignments for 2n people to minimize total travel costs efficiently…

距离顺序排列矩阵单元格

Compute all matrix cell coordinates sorted by Manhattan distance from a given center using array and math techniques eff…

两个无重叠子数组的最大和

Find the maximum sum of two non-overlapping subarrays by efficiently using state transition dynamic programming.

字符流

Implement a StreamChecker that detects if any suffix of a character stream matches a given list of words using efficient…

边界着色

Given a grid and a starting cell, color all border cells of the connected component using DFS while preserving interior …

不相交的线

The Uncrossed Lines problem involves finding the maximum number of non-intersecting lines that can be drawn between two …

逃离大迷宫

The 'Escape a Large Maze' problem involves navigating a massive grid with blocked squares and finding if a target can be…

有效的回旋镖

Determine if three points on a 2D plane form a boomerang, based on distinctness and non-collinearity.

多边形三角剖分的最低得分

Compute the minimum total score to triangulate a convex polygon using state transition dynamic programming on vertex val…

移动石子直到连续 II

Determine the minimum and maximum moves to make stones consecutive using sliding window and endpoint adjustments efficie…

分隔数组以得到最大和

Partition an array into subarrays of length at most k, replacing each with its maximum to maximize total sum efficiently…

最后一块石头的重量

In the 'Last Stone Weight' problem, we smash the two heaviest stones until one remains, using heaps or sorting.

最长字符串链

Find the longest word chain by scanning arrays and using hash lookups to efficiently track predecessor-successor sequenc…

最后一块石头的重量 II

In the 'Last Stone Weight II' problem, you need to find the minimal possible stone weight after a series of smashes usin…

高度检查器

Determine how many students are out of place in a line by comparing their heights to the sorted expected order efficient…

爱生气的书店老板

Maximize satisfied customers in a bookstore by strategically suppressing the owner's grumpy minutes using a sliding wind…

交换一次的先前排列

Find the lexicographically largest permutation smaller than the given array using exactly one swap, leveraging a greedy …

距离相等的条形码

Rearrange barcodes in an array so that no two adjacent elements are equal, using a greedy approach and hash table for ef…

按列翻转得到最大值等行数

Maximize the number of equal rows in a binary matrix by flipping any number of columns.

负二进制数相加

Add two numbers represented in negabinary format and return the result in the same format.

元素和为目标值的子矩阵数量

Count all non-empty submatrices in a given matrix whose elements sum exactly to the target using efficient scanning tech…

复写零

Duplicate each zero in a fixed-length array in place, shifting elements right using a two-pointer scanning approach effi…

受标签影响的最大值

Maximize the sum of selected item values while respecting label use limits using array scanning and hash tracking.

二进制矩阵中的最短路径

Find the shortest clear path in a binary matrix using BFS, carefully handling obstacles and diagonal movements for effic…

大样本统计

Calculate minimum, maximum, mean, median, and mode from a large sample represented by an array of counts.

拼车

Determine if a car can handle multiple trips without exceeding its capacity using array sorting and event simulation tec…

山脉数组中查找目标值

Find in Mountain Array requires locating a target using binary search over a peak-structured array efficiently in intera…

填充书架

Determine the minimum total height of a bookcase by placing books in order using state transition dynamic programming.

航班预订统计

Solve Corporate Flight Bookings by marking range changes once, then building final seat totals with a single prefix sum …

删点成林

Delete nodes from a binary tree using array scanning and hash lookup to return the remaining forest efficiently.

数组的相对排序

Sort arr1 by the relative order of arr2, with remaining elements placed in ascending order.

表现良好的最长时间段

The Longest Well-Performing Interval problem challenges you to find the longest subarray where tiring days exceed non-ti…

最小的必要团队

Find the smallest subset of people covering all required skills using bitmask dynamic programming for efficient state tr…

等价多米诺骨牌对的数量

Count all pairs of dominoes that are equivalent by scanning the array and using a hash table for fast lookup.

叶值的最小代价生成树

Compute the minimum sum of non-leaf nodes in a binary tree formed from array leaves using dynamic programming efficientl…

绝对值表达式的最大值

Calculate the largest sum of absolute differences across two arrays and their indices using an efficient pattern-based a…

最大的以 1 为边界的正方形

Find the largest square of 1s with 1s on its borders in a binary grid using dynamic programming.

石子游戏 II

Stone Game II is a dynamic programming problem where Alice and Bob alternate taking stones from piles to maximize their …

递减元素使数组呈锯齿状

Transform any integer array into a zigzag pattern with minimal decrements using a targeted greedy approach and invariant…

快照数组

Implement a SnapshotArray that efficiently tracks element changes and retrieves past states using array scanning and has…

子数组中占绝大多数的元素

Efficiently find the majority element in any subarray using a data structure optimized for multiple range queries.

拼写单词

Compute the total length of words that can be fully constructed from given characters using array scanning and hash mapp…

地图分析

Find the farthest water cell from land in a grid and return the Manhattan distance using state transition dynamic progra…

查询无效交易

Detect invalid transactions by scanning arrays and cross-checking with hash tables for time, amount, and city conflicts …

比较字符串最小字母出现频次

Compare Strings by Frequency of the Smallest Character requires counting minimal character frequencies in words and quer…

构建回文串检测

Given a string and queries, determine if a substring can be rearranged and modified to form a palindrome.

猜字谜

Solve the "Number of Valid Words for Each Puzzle" problem with array scanning and hash lookup to efficiently count valid…

公交站间的距离

Compute the minimal distance between two bus stops on a circular route using an array-driven solution approach.

删除一次得到子数组最大和

Find the maximum sum of a subarray with at most one deletion in this dynamic programming problem.

使数组严格递增

Determine the minimum operations to transform arr1 into a strictly increasing sequence using values from arr2 efficientl…

K 次串联后最大子数组之和

Solve the K-Concatenation Maximum Sum problem using dynamic programming and optimal sub-array sum calculation.

最小绝对差

Find all pairs with the minimum absolute difference between two elements in an array, and return them in ascending order…

交换字符串中的元素

Find the lexicographically smallest string by swapping characters in given pairs of indices.

独一无二的出现次数

Determine if each integer in an array occurs a unique number of times using efficient hash-based counting and verificati…

穿过迷宫的最少移动次数

Find the minimum moves for a 2-cell snake to reach the bottom-right corner using rotations and BFS traversal in a grid.

玩筹码

Compute the minimum cost to move all chips to one position using parity-based greedy moves efficiently.

最长定差子序列

Find the longest arithmetic subsequence with a given difference using dynamic programming and hash tables.

黄金矿工

Find the path with the maximum gold in a grid with backtracking and pruning techniques to maximize the gold collected.

可以攻击国王的皇后

Identify all black queens on an 8x8 chessboard that can attack the white king using array and matrix simulation techniqu…

掷骰子模拟

Calculate all valid sequences of n dice rolls with consecutive roll constraints using state transition dynamic programmi…

最大相等频率

Find the longest prefix of an array where removing one element makes all numbers appear equally, using efficient hash tr…

缀点成线

Determine if a series of coordinates form a straight line on a 2D plane using geometry and mathematical principles.

删除子文件夹

Remove sub-folders in a filesystem by filtering out folders nested inside other folders.

规划兼职工作

Compute the maximum profit from non-overlapping jobs using state transition dynamic programming with sorted arrays and b…

串联字符串的最大长度

Find the maximum length of a concatenated string from an array with all unique characters using backtracking search with…

统计「优美子数组」

The problem requires counting subarrays with exactly k odd numbers using an efficient array scanning approach.

检查「好数组」

Determine if a given array of positive integers can generate 1 using integer multiples of any subset, leveraging number …

奇数值单元格的数目

This problem involves updating a matrix based on given indices and counting cells with odd values afterward.

重构 2 行二进制矩阵

Reconstruct a 2-row binary matrix by distributing column sums while respecting upper and lower row limits using greedy p…

统计封闭岛屿的数目

Count the number of closed islands in a 2D grid using array traversal and depth-first search efficiently.

得分最高的单词集合

Calculate the highest total score by selecting words from a list using available letters, respecting individual letter s…

二维网格迁移

Shift 2D Grid requires shifting elements of a matrix by a given number of times, simulating step-by-step movement.

可被三整除的最大和

Find the maximum sum divisible by three from a given array using dynamic programming and state transition.

推箱子

Solve the minimum moves to push a box to its target using BFS and priority handling in a grid-based warehouse layout eff…

访问所有点的最小时间

Calculate the minimum seconds required to visit all given 2D points in order using optimal diagonal or straight moves.

统计参与通信的服务器

Count Servers that Communicate involves identifying servers in a grid that can communicate based on row or column connec…

搜索推荐系统

Design a search suggestion system that provides the top three lexicographically smallest products matching a search word…

找出井字棋的获胜者

Determine the winner of a Tic Tac Toe game by scanning moves and using hash lookups for rows, columns, and diagonals eff…

统计全为 1 的正方形子矩阵

Count the number of square submatrices with all ones in a given binary matrix using dynamic programming.

用户分组

Organize people into groups based on their specified group sizes using array scanning and hash table bucketing efficient…

使结果不超过阈值的最小除数

Find the smallest divisor such that the sum of all divided array elements is less than or equal to the threshold.

转化为全零矩阵的最少反转次数

Compute the minimum flips to convert a binary matrix to zero by toggling cells and neighbors using array scanning plus h…

有序数组中出现次数超过25%的元素

Identify the integer occurring more than 25% in a sorted array using a precise array-driven search strategy for efficien…

删除被覆盖区间

Remove all intervals fully covered by another using sorting and linear traversal, counting only distinct remaining inter…

下降路径最小和 II

Find the minimum sum of a falling path in a square matrix using dynamic programming while avoiding same-column selection…

元素和小于等于阈值的正方形的最大边长

This problem challenges you to find the largest square in a matrix with a sum below a given threshold using binary searc…

网格中的最短路径

Find the shortest path in a grid with obstacles, allowing the elimination of up to k obstacles using BFS.

统计位数为偶数的数字

Count the integers in an array that have an even number of digits using a direct array traversal with digit math.

划分数组为连续数字的集合

Determine if an integer array can be partitioned into sets of k consecutive numbers using array scanning and hash mappin…

你能从盒子里获得的最大糖果数

Collect maximum candies from boxes by exploring initially available boxes and using keys to unlock additional ones effic…

将每个元素替换为右侧最大元素

Replace every element in an array with the greatest element on its right side, and replace the last element with -1.

转变数组后最接近目标值的数组和

Find the integer that mutates all larger elements in an array to minimize the sum difference to a target efficiently.

最大得分的路径数目

Calculate the maximum score path and count all valid routes in a square board with obstacles using dynamic programming.

和为零的 N 个不同整数

Generate an array of n unique integers that sum to zero using a symmetric pairing strategy to ensure balance.

跳跃游戏 III

Jump Game III challenges you to determine if you can reach any zero in an array using jumps defined by array values, tes…

口算难题

Check if a verbal arithmetic equation can be solved using a valid digit-letter mapping.

子数组异或查询

Compute XOR results for multiple subarray queries using efficient prefix XOR to reduce repeated computation overhead in …

获取你好友已观看的视频

Find videos watched by friends up to a given level and return them sorted by frequency and alphabetically.

解压缩编码列表

Decompress a run-length encoded list by expanding each pair into repeated values based on frequency.

矩阵区域和

Compute a matrix where each cell contains the sum of all elements within k-distance blocks using prefix sums efficiently…

竖直打印单词

Transform a string into vertical columns by arranging each word character in array positions while trimming trailing spa…

灌溉花园的最少水龙头数目

Determine the minimum number of taps to water an entire garden using state transition dynamic programming and interval c…

将矩阵按对角线排序

Sort each diagonal of a matrix in ascending order, applying sorting and matrix traversal techniques.

翻转子数组得到最大的数组值

Maximize the value of an array by reversing a subarray, focusing on greedy choices and invariant validation.

数组序号转换

Transform the elements of an array into their ranks, where the rank represents the size order of the elements.

餐厅过滤器

Filter restaurants by vegan-friendly status, price, and distance, and sort them by rating and ID.

工作计划的最低难度

Schedule jobs into multiple days to minimize the difficulty of the schedule using dynamic programming and state transiti…

矩阵中战斗力最弱的 K 行

Find the k weakest rows in a binary matrix where rows contain soldiers and civilians, using sorting and binary search te…

数组大小减半

This problem asks to minimize the set of integers removed to reduce an array's size to at least half by removing occurre…

跳跃游戏 V

Jump Game V is a hard dynamic programming problem that focuses on maximizing jumps between indices in an array.

大小为 K 且平均值大于等于阈值的子数组数目

Given an array, find the number of sub-arrays of size k with an average greater than or equal to a given threshold.

跳跃游戏 IV

Jump Game IV requires minimizing steps to reach the last index using jumps across equal values and neighbors efficiently…

检查整数及其两倍数是否存在

Solve Check If N and Its Double Exist by scanning once and checking doubles or halves in a hash set.

参加考试的最大学生数

Calculate the maximum number of students who can take an exam without cheating using state transition dynamic programmin…

统计有序矩阵中的负数

Count Negative Numbers in a Sorted Matrix requires counting negative numbers in a matrix sorted in non-increasing order …

最后 K 个数的乘积

Design a data structure to efficiently return the product of the last k numbers in a dynamic integer stream using prefix…

最多可以参加的会议数目

Maximize the number of events you can attend given their start and end days using a greedy strategy.

多次求和构造目标数组

This problem requires constructing a target array from an array of ones, using multiple sum operations and a priority qu…

根据数字二进制下 1 的数目排序

Sort an array of integers by the number of 1's in their binary representation and then by their value in case of ties.

每隔 n 个顾客打折

Compute customer bills with periodic discounts efficiently using array scanning and hash mapping for fast product price …

形成三的最大倍数

Find the largest number divisible by three by selecting and ordering digits optimally using state transition dynamic pro…

有多少小于当前数字的数字

In this problem, you need to determine how many numbers are smaller than each element in an array, focusing on array sca…

通过投票对团队排名

Rank Teams by Votes requires counting position-based votes and resolving ties with array scanning and hash lookup techni…

使网格图至少有一条有效路径的最小代价

Determine the minimum cost to create at least one valid path from the top-left to bottom-right in a directional grid.

二进制字符串前缀一致的次数

Count how many times a 1-indexed binary string becomes prefix-aligned as bits are flipped sequentially using an array-dr…

矩阵中的幸运数

The Lucky Numbers in a Matrix problem involves finding elements that are the minimum in their row and maximum in their c…

设计一个支持增量操作的栈

Implement a stack that supports push, pop, and targeted increment operations efficiently using array-based state managem…

最大的团队表现值

Maximize the performance of a team by selecting up to k engineers with the highest performance based on speed and effici…

两个数组间的距离值

Calculate the distance value between two integer arrays by determining how many elements in arr1 don't have a close coun…

安排电影院座位

Determine the maximum number of four-person groups that can be seated in a cinema using array scanning and hash lookup e…

3n 块披萨

Maximize your pizza slice sum from a 3n-sized circular array using state transition dynamic programming efficiently.

按既定顺序创建目标数组

Learn how to efficiently create a target array by inserting elements at specified indices using array simulation techniq…

四因数

Compute the sum of all divisors for numbers in an array that have exactly four divisors using array and math techniques.

检查网格中是否存在有效路径

Check if there is a valid path from the upper-left to the bottom-right corner of a grid using depth-first search.

找出数组中的幸运数

Identify the largest lucky integer in an array by counting frequencies and comparing values with their occurrences effic…

统计作战单位数

Count the number of valid three-soldier teams using ratings with a state transition dynamic programming approach efficie…

做菜顺序

Maximize the sum of like-time coefficients by optimally choosing dishes to prepare in this dynamic programming problem.

非递增顺序的最小子序列

Find the minimum subsequence in non-increasing order such that its sum exceeds the sum of non-included elements.

石子游戏 III

Stone Game III is a challenging dynamic programming problem based on game theory and state transition logic.

数组中的字符串匹配

Identify all strings in an array that appear as substrings of other strings, focusing on array and string matching patte…

查询带键的排列

This problem involves processing queries on a permutation using an array and binary indexed tree for efficient results.

逐步求和得到正数的最小值

Find the minimum starting value to ensure the step-by-step sum of an array is always at least 1.

点菜展示表

Generate a restaurant display table from orders by counting each food item per table using array scanning and hash looku…

可获得的最大点数

Maximize your score by selecting k cards from the beginning or end of the array using a sliding window approach.

对角线遍历 II

Traverse a jagged 2D array diagonally by grouping elements with equal row and column sums efficiently using sorting and …

带限制的子序列和

Solve the Constrained Subsequence Sum problem using dynamic programming, sliding window, and priority queues to maximize…

拥有最多糖果的孩子

Determine which kids, after receiving extra candies, will have the greatest number of candies in a group.

每个人戴不同帽子的方案数

Calculate all unique assignments of hats to people using state transition dynamic programming with bitmasking for collis…

旅行终点站

Find the destination city from a list of paths where each path connects two cities. The city with no outgoing path is th…

是否所有 1 都至少相隔 k 个元素

Check if all 1's in a binary array are at least k places away from each other.

绝对差不超过限制的最长连续子数组

Find the longest subarray with elements whose absolute difference is within a specified limit using a sliding window app…

有序矩阵中的第 k 个最小数组和

Find the kth smallest sum in a matrix with sorted rows using binary search and a heap-based approach.

用栈操作构建数组

Simulate stack operations to match a target array while processing numbers from 1 to n.

形成两个异或相等数组的三元组数目

Efficiently count all triplets in an array where two subarrays formed by splitting have equal XOR using array scanning a…

切披萨的方案数

This problem challenges you to determine the number of valid ways to cut a pizza into pieces with apples using dynamic p…

数位成本和为目标值的最大数字

Maximize the integer you can paint with given digit costs under a target sum, using dynamic programming to optimize the …

在既定时间做作业的学生人数

Count the number of students doing homework at a given time using an array-driven solution approach.

收藏清单

Identify people whose favorite companies lists are unique and not subsets of any other person's list using efficient arr…

圆形靶内的最大飞镖数量

Maximize the number of darts on a circular dartboard given dart positions and radius.

两个子序列的最大点积

Solve Max Dot Product of Two Subsequences with state transition dynamic programming that enforces a non-empty pairing de…

通过翻转子数组使两个数组相等

Solve Make Two Arrays Equal by Reversing Subarrays by checking whether target and arr contain the same values with match…

摘樱桃 II

Maximize cherry collection in a grid using two robots with careful state transition dynamic programming to optimize path…

数组中两元素的最大乘积

Find the maximum product of two elements in an array by carefully selecting indices and leveraging sorting for efficienc…

切割后面积最大的蛋糕

Maximize the area of a piece of cake after specified horizontal and vertical cuts using greedy algorithms and sorting.

两个盒子中球的颜色数相同的概率

Compute the probability that two boxes contain the same number of distinct balls using careful combinatorial and DP meth…

重新排列数组

Shuffle the Array requires an efficient approach to rearrange elements using an array-driven solution strategy with two …

数组中的 k 个最强值

Identify the k strongest values in an array using two-pointer scanning and careful tracking of the array's centre value.

设计浏览器历史记录

Implement a browser history tracker with back, forward, and visit operations using linked-list pointer manipulation effi…

粉刷房子 III

Solve Paint House III using state transition dynamic programming to minimize painting costs while forming exact neighbor…

商品折扣后的最终价格

Calculate final prices with discounts applied in a shop using a stack-based state management approach to find the correc…

子矩形查询

Implement the SubrectangleQueries class to handle dynamic updates and value queries on a 2D rectangle.

找两个和为目标值且不重叠的子数组

Find two non-overlapping sub-arrays with a given target sum and return the minimal total length efficiently using array …

安排邮筒

Allocate k mailboxes to houses along a street minimizing total distance using dynamic programming with state transitions…

一维数组的动态和

Calculate the running sum of a given 1D array by updating each element to the sum of itself and all previous elements.

不同整数的最少数目

Find the least number of unique integers after removing exactly k elements from an array using efficient frequency count…

制作 m 束花所需的最少天数

Determine the minimum number of days required to make m bouquets using k adjacent flowers efficiently with binary search…

保证文件名唯一

This problem requires creating unique folder names by appending suffixes to duplicate names using an array scanning and …

避免洪水泛滥

This problem asks you to avoid flooding by deciding when to dry lakes between rain events.

去掉最低工资和最高工资后的工资平均值

Calculate the average salary of employees, excluding the highest and lowest salaries, from an array of unique salaries.

删掉一个元素以后全为 1 的最长子数组

Solve LeetCode 1493 by tracking runs of 1s around one deletion using a tight sliding window or state transition DP.

检查数组对是否可以被 k 整除

Check if array pairs are divisible by k by pairing elements whose sums are divisible by k using array scanning and hash …

满足条件的子序列数目

Count all non-empty subsequences in an integer array where the sum of the minimum and maximum elements is at most a targ…

满足不等式的最大值

Max Value of Equation asks to find the maximum value of a specific equation on a set of 2D points using sliding window t…

判断能否形成等差数列

Determine if a given array can be rearranged into a valid arithmetic progression using sorting and consecutive differenc…

所有蚂蚁掉下来前的最后一刻

This problem involves simulating ant movement on a plank to determine the last moment before all ants fall off.

统计全 1 子矩形

Count Submatrices With All Ones is a dynamic programming problem focusing on submatrix counting using an efficient row-b…

子数组和排序后的区间和

Compute the sum of sorted subarray sums efficiently using binary search over valid sum ranges and prefix sum accumulatio…

三次操作后最大值与最小值的最小差

Find the minimum difference between the largest and smallest values in an array after performing at most three moves.

好数对的数目

Count all index pairs in an array where elements match and the first index is smaller, using hash-based scanning efficie…

概率最大的路径

Find the path with the highest success probability in a graph from a start node to an end node, using edge probabilities…

服务中心的最佳位置

Find the optimal service center position in a city by minimizing the sum of Euclidean distances to all customers.

找到最接近目标值的函数值

In this problem, you'll use binary search to find the closest value of a mysterious function to a given target.

和为奇数的子数组数目

Count the number of subarrays with an odd sum using dynamic programming and prefix sum techniques.

形成目标数组的子数组最少增加次数

The problem asks for the minimum number of operations to transform an initial array of zeros into a target array using s…

重新排列字符串

Reorder characters in a string using a given indices array to reconstruct the intended output efficiently and correctly.

统计好三元组

Count Good Triplets requires identifying all triplets in an array that satisfy multiple absolute difference constraints …

找出数组游戏的赢家

Determine the integer that wins an array game by achieving k consecutive victories through simulated pairwise comparison…

排布二进制网格的最少交换次数

Compute the minimum number of adjacent row swaps to transform a binary grid so all upper-triangle cells are zero using a…

最大得分

Find the maximum possible score from two sorted arrays with a dynamic programming approach, leveraging partitioning and …

第 k 个缺失的正整数

Find the kth missing positive integer in a strictly increasing array using binary search over the answer space efficient…

和为目标值且不重叠的非空子数组的最大数目

Find the maximum number of non-overlapping subarrays that sum to a given target using efficient scanning and hash lookup…

切棍子的最小成本

Find the minimum cost to cut a stick into segments at specified positions using dynamic programming and sorting.

存在连续三个奇数的数组

Determine if an integer array contains three consecutive odd numbers using a direct array-driven solution strategy for f…

两球之间的磁力

Maximize the minimum magnetic force between balls by strategically placing them in baskets using binary search on positi…

得到目标数组的最少函数调用次数

Calculate the minimum number of modify calls needed to convert an all-zero array into a given target array using greedy …

二维网格图中探测环

Detect cycles in a 2D character grid using DFS while carefully tracking parent cells to avoid invalid revisits.

圆形赛道上经过次数最多的扇区

Determine which sectors on a circular track are visited most frequently using array and simulation techniques efficientl…

你可以获得的最大硬币数目

Solve the Maximum Number of Coins You Can Get using greedy pile selection and invariant validation to maximize your coin…

查找大小为 M 的最新分组

Determine the latest step where a contiguous group of ones of exact length m exists using array scanning and hash tracki…

石子游戏 V

In Stone Game V, Alice divides stones into rows to maximize her score, using a dynamic programming approach to try all d…

重复至少 K 次且长度为 M 的模式

Determine if a subarray of length m repeats k or more consecutive times in a given integer array efficiently.

乘积为正数的最长子数组长度

Given an array, find the maximum length of a subarray with a positive product using dynamic programming.

使陆地分离的最少天数

Find the minimum number of days to disconnect an island in a grid using depth-first search.

将子数组重新排序得到同一个二叉搜索树的方案数

Determine the number of ways to reorder an array to get the same binary search tree (BST) from its insertion order.

矩阵对角线元素的和

Calculate the sum of both primary and secondary diagonals in a square matrix while avoiding double-counting overlaps.

删除最短的子数组使剩余数组有序

Find the shortest subarray to remove in order to make an array non-decreasing using binary search and two-pointer techni…

统计所有可行路径

This problem requires counting all possible routes between cities using fuel efficiently with state transition dynamic p…

数的平方等于两数乘积的方法数

Find the number of triplets where the square of a number equals the product of two others, utilizing array scanning and …

使绳子变成彩色的最短时间

Minimize the time Bob needs to remove balloons to make a rope colorful using dynamic programming with state transitions.

二进制矩阵中的特殊位置

Identify all special positions in a binary matrix where a 1 has no other 1s in its row or column, ensuring optimal array…

统计不开心的朋友

Determine the number of unhappy friends in paired arrangements using array-based simulation for preference violations.

连接所有点的最小费用

Min Cost to Connect All Points asks for the minimum cost to connect all points on a 2D plane, using manhattan distances …

所有奇数长度子数组的和

Calculate the sum of all odd-length subarrays in a given integer array using efficient array and math strategies.

所有排列中的最大和

Maximize the total sum of requests on nums by greedily assigning larger numbers to most frequently requested indices.

使数组和能被 P 整除

Determine the minimum-length subarray to remove so the remaining array sum is divisible by a given integer p efficiently…

奇怪的打印机 II

Solve Strange Printer II by building color dependencies from bounding rectangles and checking whether a topological orde…

矩阵的最大非负积

Find the maximum non-negative product path in a matrix using dynamic programming and state transition.

连通两组点的最小成本

Compute the minimum cost to fully connect two groups of points using dynamic programming and bitmasking efficiently.

文件夹操作日志搜集器

Simulate folder navigation based on a list of operations to determine the current folder depth.

经营摩天轮的最大利润

Maximize the profit from operating a Centennial Wheel by determining the optimal number of rotations based on customer a…

最多可达成的换楼请求数目

Find the maximum number of achievable transfer requests between buildings with constraints on net employee transfers.

警告一小时内使用相同员工卡大于等于三次的人

Solve LeetCode 1604 by grouping swipe times per employee, sorting each list, and scanning for any three within 60 minute…

给定行和列的和求可行矩阵

Given row and column sums, find any valid matrix of non-negative integers that satisfies them.

找到处理最多请求的服务器

Given k servers and a series of requests, find the busiest server(s) using greedy strategies and efficient server tracki…

特殊数组的特征值

Determine if an array has exactly x elements greater than or equal to x using binary search over the answer space.

可见点的最大数目

Determine the maximum number of points visible from a fixed location within a given angle using a sliding window approac…

删除某些元素后的数组均值

Calculate the trimmed mean by removing the lowest and highest 5% of elements in an array using sorting for accuracy and …

网络信号最好的坐标

Determine the coordinate with the maximum network quality by summing signal strengths from all reachable towers efficien…

无矛盾的最佳球队

Find the highest score basketball team by choosing players without conflicts in age and score using dynamic programming.

带阈值的图连通性

In 'Graph Connectivity With Threshold,' determine if cities are connected based on common divisors exceeding a threshold…

按键持续时间最长的键

Determine which key had the longest press duration in a sequence using array indices and string mapping, resolving ties …

等差子数组

Determine whether subarrays of a given array can be rearranged to form arithmetic sequences using array scanning and has…

最小体力消耗路径

Find the minimum effort required to travel from the top-left to the bottom-right of a grid, considering height differenc…

矩阵转换后的排名

Compute a unique rank matrix using graph indegree with topological ordering, ensuring each element reflects its relative…

按照频率将数组升序排序

Sort Array by Increasing Frequency requires counting each element and ordering them by frequency, breaking ties with des…

两点之间不包含任何点的最宽垂直区域

Find the maximum width of a vertical area between points with no points inside using array sorting efficiently.

通过给定词典构造目标字符串的方案数

Calculate the number of ways to form a target string using words of equal length via state transition dynamic programmin…

能否连接形成数组

Determine if an array can be formed by concatenating subarrays without reordering individual elements, using hash lookup…

可以到达的最远建筑

Furthest Building You Can Reach explores a greedy approach with heap-based optimization to find the maximum reachable bu…

第 K 条最小指令

Find the kth smallest lexicographic instruction sequence for reaching a destination in a grid using state transition dyn…

获取生成数组中的最大值

Compute the maximum value in a generated array using defined recurrence rules, leveraging array simulation techniques ef…

销售价值减少的颜色球

Maximize total value by greedily selling diminishing-valued colored balls based on inventory and customer orders.

通过指令创建有序数组

The problem asks to compute the cost of inserting elements into a sorted array using a series of instructions.

拆炸弹

Defuse the Bomb uses a sliding window to update a circular array based on a key, with efficient state updates.

到家的最少跳跃次数

Find the minimum number of jumps needed to reach a target position while avoiding forbidden positions.

分配重复整数

Determine if you can allocate integers to satisfy customer quantities using state transition dynamic programming techniq…

设计有序流

Design an Ordered Stream that returns values in increasing order based on unique integer IDs with efficient insertion an…

将 x 减到 0 的最小操作数

Find the minimum number of operations to reduce a value x to zero by removing elements from an array.

检查两个字符串数组是否相等

Determine if two string arrays form identical strings by concatenating elements in order, handling subtle array-length m…

生成平衡数组的方案数

Solve Ways to Make a Fair Array by tracking parity sums before and after each removal with prefix-sum style accounting.

完成所有任务的最少初始能量

Determine the minimum initial energy needed to finish all tasks using a greedy ordering based on required versus actual …

设计前中后队列

Implement a queue that efficiently handles push and pop operations at the front, middle, and back using pointer manipula…

得到山形数组的最少删除次数

Solve the problem of finding the minimum number of removals to make a given array a mountain array using dynamic program…

最富有客户的资产总量

Calculate the richest customer's wealth by summing the amounts in each customer's bank accounts in a matrix.

找出最具竞争力的子序列

Identify the lexicographically smallest subsequence of size k using stack-based greedy selection in array traversal.

使数组互补的最少操作次数

Find the minimum moves to make an array complementary by analyzing paired sums and using hash lookups for efficiency.

数组的最小偏移量

Given a positive integer array, repeatedly double or halve elements to minimize the difference between its largest and s…

K 和数对的最大数目

Max Number of K-Sum Pairs is a problem involving counting disjoint pairs with a given sum k in an array.

最小不兼容性

Optimize the sum of incompatibilities when distributing an array into subsets with unique elements.

统计一致字符串的数目

Count the number of strings fully composed of allowed characters using array scanning and hash lookup for efficiency.

有序数组中差绝对值之和

Calculate the sum of absolute differences between each element and others in a sorted array efficiently.

石子游戏 VI

Determine the winner in Stone Game VI using a greedy strategy that accounts for each stone's dual value impact on Alice …

从仓库到码头运输箱子

Optimize the minimum number of trips to deliver boxes to ports under strict ship constraints using dynamic programming t…

石子游戏 VII

Maximize score difference in a two-player turn-based stone removal game using state transition dynamic programming.

堆叠长方体的最大高度

Maximize the height of stacked cuboids by strategically rotating and stacking them using dynamic programming.

删除子数组的最大得分

Maximize the score by erasing a subarray with unique elements in an array of integers.

跳跃游戏 VI

Jump Game VI challenges you to maximize your score while jumping through an array using state transition dynamic program…

检查边长度限制的路径是否存在

Solve the problem of checking if there exists a path between two nodes under edge length constraints using efficient tec…

无法吃午餐的学生数量

Simulate a queue of students with sandwich preferences and determine how many can't eat based on available sandwiches.

平均等待时间

Compute the average waiting time for customers using array traversal and simulation of a single chef processing orders s…

得到连续 K 个 1 的最少相邻交换次数

Find the minimum number of adjacent swaps to gather k consecutive ones in a binary array using sliding window logic.

吃苹果的最大数目

Maximize apples eaten by choosing the best apples first, considering their rot days and available days to eat them.

球会落何处

Determine where each ball exits a diagonal board grid or if it gets stuck, using matrix simulation with careful traversa…

与数组中元素的最大异或值

Solve the Maximum XOR With an Element From Array problem by efficiently finding the maximum XOR for each query using bit…

卡车上的最大单元数

Maximize total units loaded on a truck by choosing boxes greedily based on highest units per box within truck capacity l…

大餐计数

Count Good Meals asks you to find pairs of food items with a sum of deliciousness equal to a power of two.

将数组分成三个子数组的方案数

The problem requires finding the number of ways to split an array into three subarrays where each split meets a certain …

得到子序列的最少操作次数

Compute the minimum insertions required to transform arr so that target becomes its subsequence using array scanning and…

构建字典序最大的可行序列

Construct the Lexicographically Largest Valid Sequence problem involves finding the largest sequence with backtracking a…

解码异或后的数组

Recover the original integer array from its XOR-encoded version using direct bitwise manipulation and sequential reconst…

执行交换操作后的最小汉明距离

Solve Minimize Hamming Distance After Swap Operations by grouping swappable indices and matching value counts inside eac…

完成所有工作的最短时间

Minimize the maximum working time of k workers by optimally assigning jobs, leveraging dynamic programming and bit manip…

可以形成最大正方形的矩形数目

Determine how many rectangles can be trimmed to form the largest possible square using an array-driven solution strategy…

同积元组

Given an array of distinct integers, return the number of tuples where the product of two pairs is the same.

重新排列后的最大子矩阵

Rearrange columns of a binary matrix to find the largest submatrix of 1s.

猫和老鼠 II

Cat and Mouse II requires determining if the mouse can reach food before being caught using graph and topological orderi…

找到最高海拔

Find the highest altitude after a series of altitude changes during a road trip using prefix sum technique.

需要教语言的最少人数

Minimize the number of users to teach a language that ensures all friends can communicate in a social network.

解码异或后的排列

Decode XORed Permutation uses prefix reconstruction with global XOR to recover the hidden odd-length permutation in line…

生成乘积数组的方案数

Determine the number of arrays of size n where the product equals k using prime factorization and combinatorial DP techn…

找出第 K 大的异或坐标值

Compute the kth largest XOR coordinate in a 2D matrix using prefix sums, bit manipulation, and optimized selection techn…

从相邻元素对还原数组

Restore the Array From Adjacent Pairs reconstructs a sequence using adjacent element pairs. Efficient hash lookups and a…

你能在你最喜欢的那天吃到你最喜欢的糖果吗？

Determine if you can eat a candy of your favorite type on a specific day, given daily limits and candy availability.

唯一元素的和

Given an array, find the sum of all its unique elements by identifying those that appear only once.

任意子数组和的绝对值的最大值

Solve for the maximum absolute sum of any subarray using dynamic programming and understanding state transitions.

最多可以参加的会议数目 II

Determine the maximum sum of event values you can collect by attending at most k non-overlapping events using DP.

检查数组是否经排序和轮转得到

Determine if a given integer array is sorted in non-decreasing order and then rotated, handling duplicates correctly.

最接近目标值的子序列和

Find the minimum absolute difference between a target goal and any subsequence sum using optimized dynamic programming a…

袋子里最少数目的球

Find the minimum penalty (maximum balls in a bag) after performing up to maxOperations to split bags of balls.

通过连接另一个数组的子数组得到一个数组

Determine if you can sequentially select disjoint subarrays from nums matching each group in order using two-pointer sca…

地图中的最高点

Solve the Map of Highest Peak problem using breadth-first search to assign heights based on proximity to water cells.

互质树

Determine the closest coprime ancestor for each node in a tree using efficient traversal and state tracking of node valu…

移动所有球到每个盒子所需的最小操作数

Solve the problem of finding the minimum operations to move balls to each box using an efficient approach with arrays an…

执行乘法运算的最大分数

Solve the Maximum Score from Performing Multiplication Operations problem using dynamic programming and state transition…

统计匹配检索规则的物品数量

Count Items Matching a Rule is an easy problem that tests array and string manipulation with conditions based on specifi…

最接近目标价格的甜点成本

Find the closest dessert cost to a target by selecting from a list of base flavors and topping combinations using dynami…

通过最少操作次数使数组的和相等

Solve the problem of balancing the sums of two integer arrays with minimal operations, using array scanning and hash loo…

车队 II

Car Fleet II involves calculating collision times between cars traveling at different speeds along a one-lane road using…

找到最近的有相同 X 或 Y 坐标的点

Find the nearest point with the same x or y coordinate using Manhattan distance. Return its index or -1 if none exists.

统计点对的数目

Given a graph with nodes and edges, count pairs of nodes where the degree sum exceeds a given threshold for each query.

构成特定和需要添加的最少元素

Compute the gap between current sum and goal, then greedily cover it with limit-sized additions to get the minimum count…

使所有区间的异或结果为零

Determine the minimum changes needed in an array so all size-k segments XOR to zero using DP and bit manipulation.

最大平均通过率

Maximize the average pass ratio by assigning extra guaranteed-passing students using a greedy heap strategy for optimal …

好子数组的最大分数

Maximize the score of a good subarray using binary search to explore the valid answer space with a focus on two-pointer …

你能构造出连续值的最大数目

Find the maximum number of consecutive integer values starting from zero that can be formed using your coins array.

N 次操作后的最大分数和

Maximize the score after n operations by selecting pairs from the array and using their GCD with dynamic programming or …

最大升序子数组和

Solve Maximum Ascending Subarray Sum by scanning once, extending rising runs, and resetting the running sum at each drop…

积压订单中的订单总数

Determine the total number of unfulfilled buy and sell orders using heaps to simulate backlog processing efficiently in …

统计异或值在范围内的数对有多少

Count all pairs in an array whose XOR falls within a given range using efficient bit manipulation techniques and a trie …

还原排列的最少操作步数

Find the minimum number of operations to reinitialize a permutation of size n using specific operations.

替换字符串中的括号内容

Quickly evaluate a string with bracketed keys using array scanning and hash table lookups for efficient replacements.

句子相似性 III

Sentence Similarity III asks if one sentence can be transformed into another by inserting a sentence inside it.

统计一个数组中好对子的数目

Count Nice Pairs in an Array requires efficiently pairing numbers where nums[i] + rev(nums[j]) equals nums[j] + rev(nums…

得到新鲜甜甜圈的最多组数

Reorder groups to maximize happy customers by using state transition dynamic programming with bitmasking for optimal bat…

截断句子

Truncate a sentence to contain only the first k words by converting it into an array of words.

查找用户活跃分钟数

This problem requires counting unique minutes of user activity on LeetCode based on a series of logs and an integer k.

绝对差值和

Minimize the absolute sum difference between two integer arrays by replacing at most one element from the first array.

序列中不同最大公约数的数目

Given an array of positive integers, find the number of different subsequences' GCDs.

数组元素积的符号

Determine the sign of a product from an integer array using a single pass without computing the full product.

找出游戏的获胜者

Find the winner of a circular game by simulating the elimination process with a queue-driven approach.

最少侧跳次数

Solve the Minimum Sideway Jumps problem using state transition dynamic programming to minimize side jumps while navigati…

最少操作使数组递增

Calculate the minimum number of increments required to transform a given integer array into a strictly increasing sequen…

统计一个圆中点的数目

Determine how many 2D points lie within multiple circles using array iteration and Euclidean distance calculations effic…

每个查询的最大异或值

Find the maximum XOR for each query based on a sorted array and bit manipulation.

雪糕的最大数量

Maximize the number of ice cream bars a boy can buy by applying a greedy choice strategy based on cost sorting.

单线程 CPU

Simulate task processing with a single-threaded CPU by sorting and prioritizing tasks based on arrival and processing ti…

所有数对按位与结果的异或和

Compute the XOR sum of all pairwise ANDs between two integer arrays using array and bitwise math techniques efficiently.

最高频元素的频数

Maximize the frequency of an element in an array by incrementing at most `k` elements. Use binary search and greedy tech…

最高建筑高度

Find the maximum building height in a city given height restrictions for specific buildings.

减小和重新排列数组后的最大元素

Determine the maximum value in an array after decreasing elements and rearranging using a greedy invariant approach.

最近的房间

Find the closest hotel room meeting minimum size requirements using binary search over the valid answer space efficientl…

到目标元素的最小距离

Solve Minimum Distance to the Target Element by scanning the array and tracking the smallest distance from start.

包含每个查询的最小区间

Find the smallest interval containing each query efficiently using binary search.

人口最多的年份

Find the earliest year with the highest population using an array plus counting approach.

下标对中的最大距离

Find the maximum distance between a pair of values in two non-increasing integer arrays using binary search.

子数组最小乘积的最大值

The problem asks to find the maximum min-product of any non-empty subarray of nums.

旋转盒子

Rotate a box represented by a character matrix, letting stones fall under gravity using precise two-pointer scanning and…

向下取整数对和

The problem asks to calculate the sum of floor divisions for all pairs in a given integer array, using an efficient meth…

找出所有子集的异或总和再求和

Compute the sum of all subset XOR totals using a backtracking search with pruning for arrays of small size.

找出和为指定值的下标对

Efficiently track and count pairs across two arrays using array scanning plus hash lookup to support dynamic updates.

准时到达的列车最小时速

This problem asks to find the minimum speed of trains to reach on time using binary search.

石子游戏 VIII

Stone Game VIII requires calculating maximum score difference using state transition dynamic programming on prefix sums …

数组中最大数对和的最小值

Minimize the maximum pair sum in an array by optimally pairing its elements.

矩阵中最大的三个菱形和

Find the three largest distinct rhombus sums from a given grid using array and math techniques.

两个数组最小的异或值之和

Minimize the XOR sum of two integer arrays by rearranging elements using dynamic programming and bit manipulation.

使用服务器处理任务

Assign tasks to servers efficiently using arrays and heaps, resolving ties by weight and index while tracking availabili…