枚举

计数质数

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

最大回文数乘积

Find the largest palindromic number from the product of two n-digit integers using math and enumeration efficiently.

模糊坐标

Find all valid 2D coordinate possibilities for an ambiguous input string using backtracking and pruning techniques.

连续整数求和

Find the number of ways to express a number as the sum of consecutive positive integers.

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…

重新排序得到 2 的幂

Determine if a number's digits can be rearranged to form a power of two using counting and hash-based checks.

超级回文数

Count all super-palindromes in a given numeric range, where each is a palindrome and square of a palindrome.

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.

强整数

Find all integers that can be expressed as x^i + y^j up to a given bound using a Hash Table plus Math approach.

顺次数

Find all integers within a range whose digits form a strictly increasing consecutive sequence using enumeration techniqu…

统计好三元组

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

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.

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.

统计子树中城市之间最大距离

This problem asks you to count subtrees in a tree structure where the maximum distance between any two cities matches sp…

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…

执行操作后字典序最小的字符串

Optimize a string through rotations and additions to get the lexicographically smallest possible result using string man…

统计只差一个字符的子串数目

Count all substrings from s that differ by exactly one character from some substring in t using precise substring compar…

一个图中连通三元组的最小度数

Find the minimum degree of a connected trio in a graph using enumeration over nodes and edges.

将字符串拆分为递减的连续值

Check if a string of digits can be split into descending consecutive values where the difference between them is 1.

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.

统计平方和三元组的数目

Count Square Sum Triples asks to find the number of integer triples where a² + b² = c² for values between 1 and n.

三除数

Determine if a given integer has exactly three positive divisors.

检查操作是否合法

Determine if a move on an 8x8 board is legal by validating lines in all directions using array and matrix patterns.

统计特殊四元组

Count Special Quadruplets requires scanning arrays and using hash lookups to efficiently find quadruplets matching sum c…

重复 K 次的最长子序列

Find the longest subsequence repeated k times in a string using backtracking search with pruning.

判断单词是否能放入填字游戏内

Determine if a word fits in a crossword grid using array and matrix checks, accounting for spaces, letters, and blocked …

分割数组的最多方案数

Determine the maximum number of ways to split an array into equal sums using at most one element change, leveraging pref…

统计按位或能得到最大值的子集数目

Determine the number of non-empty subsets that achieve the maximum bitwise OR using efficient backtracking and pruning s…

下一个更大的数值平衡数

Find the smallest numerically balanced number greater than a given integer using backtracking search and pruning.

k 镜像数字的和

This problem requires finding the sum of the n smallest k-mirror numbers by generating palindromes in base-k and base-10…

找出 3 位偶数

Generate unique 3-digit even numbers from a given array of digits with duplicates.

还原原数组

Recover the Original Array helps you understand how to reverse-engineer an array from two subsets using array scanning a…

基于陈述统计最多好人数

Determine the maximum number of good people in a group given mutual statements, using precise backtracking with pruning.

设置时间的最少代价

Calculate the minimum fatigue to set a microwave cooking time using digit moves and pushes efficiently.

拿出最少数目的魔法豆

Determine the minimum beans to remove so all remaining non-empty bags have equal beans using a greedy approach.

射箭比赛中的最大得分

In the "Maximum Points in an Archery Competition" problem, Bob aims to maximize his score while respecting Alice's arrow…

向表达式添加括号后的最小结果

Enumerate every valid parenthesis placement around the plus sign and choose the expression with the smallest evaluated p…

花园的最大总美丽值

Determine the maximum total beauty of gardens by strategically planting flowers using binary search over achievable flow…

买钢笔和铅笔的方案数

Calculate all distinct ways to spend a fixed total on pens and pencils using a straightforward enumeration strategy.

节点序列的最大得分

Find the maximum score of a valid node sequence in an undirected graph with given node scores and edges.

统计圆内格点数目

Count the number of lattice points inside at least one circle in a grid, based on given center and radius data.

移除指定数字得到的最大结果

Determine the largest possible number by removing one specific digit using a greedy approach and string iteration.

含最多 K 个可整除元素的子数组

Count all distinct subarrays with at most k elements divisible by p using array scanning and hash lookup techniques effi…

公司命名

The "Naming a Company" problem requires determining the number of valid distinct company names from a list of name ideas…

兼具大小写的最好英文字母

Find the greatest English letter that exists in both lowercase and uppercase in a string using a hash table approach.

个位数字为 K 的整数之和

Determine the minimum set of positive integers whose units digits match k and sum exactly to num using DP patterns.

等差三元组的数目

Count the number of arithmetic triplets in a given strictly increasing array with a specified difference.

被列覆盖的最多行数

Select exactly numSelect columns from a binary matrix to maximize rows where all ones are covered efficiently using back…

公因子的数目

The problem asks to find the number of common factors of two positive integers a and b.

有效时间的数目

Calculate how many valid digital clock times can be formed by replacing unknown digits in a string format hh:mm.

创建价值相同的连通块

Maximize the number of components in a tree with equal sums by carefully deleting edges using divisor-based logic.

反转之后的数字和

Determine if a non-negative integer can be expressed as the sum of a number and its reverse using enumeration and math r…

根据限制分割消息

Split Message Based on Limit requires dividing a string into parts with length constraints using a calculated suffix pat…

统计上升四元组

Given a permutation of numbers, count the number of increasing quadruplets using dynamic programming.

从两个数字数组里生成最小数字

Given two arrays of digits, find the smallest possible number formed by one digit from each array.

一个小组的最大实力值

Maximize the strength of a student group by carefully selecting students based on their scores, using dynamic programmin…

收集巧克力

Calculate the minimum cost to collect all chocolate types using rotations and purchases in an array-based enumeration pa…

得到整数零需要执行的最少操作数

This problem challenges you to compute the minimum operations to reduce an integer to zero using bit manipulation and st…

和等于目标值的质数对

Find all prime number pairs that sum up to a given integer n using an efficient sieve-based array approach.

最长交替子数组

Find the longest alternating subarray in a given array of integers.

黑格子的数目

Calculate the number of black blocks in a grid given a list of black cell coordinates.

特殊元素平方和

Calculate the sum of squares of special elements in a 1-indexed array using index divisibility checks efficiently.

包含三个字符串的最短字符串

Find the shortest string containing three given strings using a greedy approach while ensuring it is lexicographically s…

统计对称整数的数目

Count Symmetric Integers finds numbers where the sum of the first half of digits equals the sum of the second half withi…

生成特殊数字的最少操作

Minimize operations to make a number divisible by 25 by deleting digits. Use greedy choice and invariant validation.

让所有学生保持开心的分组方法数

The Happy Students problem asks how many ways a teacher can select a group of students so everyone is happy, based on ce…

给小朋友们分糖果 I

Given two integers n and limit, find the number of ways to distribute n candies among 3 children, with no child receivin…

给小朋友们分糖果 II

Determine how to distribute n candies among 3 children without exceeding a limit on individual candies.

最大化数组末位元素的最少操作次数

Minimize the number of operations needed to maximize the last elements of two arrays with specific swaps.

统计美丽子字符串 I

Given a string and a value k, count the number of beautiful substrings where vowels * consonants % k == 0.

找出峰值

Identify all peaks in a mountain array using direct array enumeration and strict neighbor comparisons efficiently.

关闭分部的可行集合数目

Calculate all valid sets of branch closures while keeping remaining branches within maxDistance using bitmask and graph …

统计移除递增子数组的数目 I

Count the number of incremovable subarrays in an array by removing them to create a strictly increasing sequence.

移除栅栏得到的正方形田地的最大面积

This problem challenges you to calculate the largest square area possible by removing fences from a given rectangular fi…

捕获黑皇后需要的最少移动次数

Determine the fewest moves to capture the black queen using only white pieces with careful position analysis.

将数组分成最小总代价的子数组 I

Divide an array into three contiguous subarrays with minimum cost by leveraging array and sorting principles.

子集中元素的最大数量

This problem asks you to find the maximum subset size where each number in the subset follows a specific pattern with ha…

人员站位的方案数 I

Calculate how many valid pairs of points can be formed on a 2D plane using array and math enumeration techniques efficie…

人员站位的方案数 II

Calculate all valid placements of people on a 2D grid ensuring Alice can fence herself with Bob without enclosing others…

出现频率最高的质数

Find the most frequent prime over 10 from numbers generated by scanning a 2D matrix in all straight directions efficient…

执行操作使数据元素之和大于等于 K

Given an array nums, find the minimum number of operations to make the sum of elements greater than or equal to k.

替换字符可以得到的最晚时间

Given a time string with "?" characters, replace them to form the latest valid 12-hour time.

构造相同颜色的正方形

Determine if a 3x3 grid can form a 2x2 square of the same color by changing at most one cell efficiently.

找出与数组相加的整数 II

Given two arrays nums1 and nums2, determine the integer added to nums1 to make it equal to nums2 after removing two elem…

使数组中所有元素相等的最小开销

Compute the minimum cost to make all elements equal using selective operations guided by greedy choices and invariant ch…

包含所有 1 的最小矩形面积 II

Find the minimum area to cover all 1's in a 2D binary grid using three non-overlapping rectangles.

三角形的最大高度

Find the maximum height of a triangle that can be formed using red and blue balls under given constraints.

统计 1 显著的字符串的数量

Count the number of substrings in a binary string with dominant ones, using a sliding window approach with state updates…

放三个车的价值之和最大 I

Maximize the value sum by placing three rooks on a chessboard while ensuring they do not attack each other.

放三个车的价值之和最大 II

Maximize the sum by placing three non-attacking rooks on a chessboard with dynamic programming.

统计近似相等数对 I

Count Almost Equal Pairs I involves finding pairs of elements that can be made equal by swapping at most one digit.

统计近似相等数对 II

Count the number of almost equal integer pairs in an array using array scanning and hash lookup efficiently.

统计好整数的数目

Count good integers by rearranging digits to form k-palindromic numbers, leveraging hash tables and math techniques.

连接二进制表示可形成的最大数值

Determine the largest number achievable by reordering three integers and concatenating their binary forms efficiently.

最小可整除数位乘积 I

Find the smallest number greater than or equal to n whose digit product is divisible by t.

识别数组中的最大异常值

Identify the largest outlier in an integer array using scanning and hash lookup for efficient detection and validation.

用点构造面积最大的矩形 I

Find the maximum area of a rectangle formed by given points on a plane with unique coordinates.

使字符频率相等的最少操作次数

This Hard problem asks to transform a string so all character frequencies match using minimal deletions, leveraging dyna…

字符相同的最短子字符串 I

Minimize the length of the longest substring with identical characters after at most numOps changes in a binary string.

从盒子中找出字典序最大的字符串 I

This problem involves finding the lexicographically largest string from a given word using a two-pointer approach.

统计特殊子序列的数目

Count the number of special subsequences in an array of positive integers, focusing on efficient array scanning and hash…

最长乘积等价子数组

This problem involves finding the longest subarray where the product equals the LCM multiplied by the GCD, leveraging a …

子数组操作后的最大频率

Determine the maximum frequency of a target value k after applying one subarray addition operation efficiently using arr…

最短公共超序列的字母出现频率

Compute all unique shortest common supersequences of given words using graph indegree tracking and topological ordering …

重新安排会议得到最多空余时间 II

Maximize free time by rescheduling at most one meeting using a greedy choice with invariant validation approach for arra…

奇偶频次间的最大差值 II

Find the maximum difference between even and odd character frequencies in substrings using sliding window updates effici…

全排列 IV

Find the k-th alternating permutation of numbers 1 to n, ensuring no adjacent numbers share parity, using array and math…

删除一个冲突对后最大子数组数目

Maximize the count of subarrays after removing one conflicting pair using array traversal and segment tree logic efficie…

不同三位偶数的数目

Given an array of digits, find how many distinct 3-digit even numbers can be formed without repetition of digits and no …

操作后最大活跃区段数 I

Maximize the number of active sections in a binary string by performing at most one trade operation.

子字符串连接后的最长回文串 I

Compute the maximum palindrome length by concatenating substrings from two strings using state transition dynamic progra…

不同 XOR 三元组的数目 II

Count all unique XOR results from triplets in an integer array using array traversal and bit manipulation techniques eff…

等和矩阵分割 I

Determine if an m x n matrix grid can be split into two non-empty sections with equal sums by making a single horizontal…

等和矩阵分割 II

Determine if a matrix can be partitioned into two sections with an equal sum using a single cut.

等积子集的划分方案

Determine if you can partition an array into two subsets with equal product using recursion and bit manipulation.

最大子数组 GCD 分数

Maximize Subarray GCD Score focuses on maximizing a subarray's score by using at most k doubling operations on an array …

找到最大三角形面积

Find the maximum area of a triangle from 2D coordinates with at least one side parallel to the x-axis or y-axis.

划分数组得到最大异或运算和与运算之和

Partition the array into three subsequences to maximize XOR and AND operations with a greedy approach.