堆（优先队列）

合并 K 个升序链表

Merge k Sorted Lists requires efficiently combining multiple sorted linked lists into one using pointers and priority qu…

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.

天际线问题

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

滑动窗口最大值

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

丑数 II

Find the nth ugly number, where ugly numbers have prime factors limited to 2, 3, and 5.

数据流的中位数

Implement a MedianFinder class that supports adding numbers and finding the median from a data stream.

前 K 个高频元素

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

设计推特

Design Twitter requires implementing post, follow, unfollow, and news feed retrieval using linked-list pointer manipulat…

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.

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…

接雨水 II

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

强密码检验器

The Strong Password Checker problem challenges you to optimize password strength while minimizing steps using greedy alg…

根据字符出现频率排序

Sort Characters By Frequency requires counting characters efficiently and rearranging a string in descending frequency o…

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…

IPO

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

相对名次

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

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…

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…

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.

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…

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…

数据流中的第 K 大元素

Find the kth largest element in a dynamic stream using binary-tree traversal and efficient state tracking with a min-hea…

网络延迟时间

Find the minimum time for a signal to travel to all nodes in a directed graph or determine if it's impossible.

重构字符串

Reorganize a string so that no two adjacent characters are the same, if possible, using a greedy approach.

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.

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.

K 站中转内最便宜的航班

Find the cheapest flight from a source to a destination with at most K stops using graph traversal techniques efficientl…

考场就座

Simulate an exam room where each student chooses a seat maximizing distance to others, using design plus heap structures…

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…

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.

最低加油次数

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

细分图中的可到达节点

The Reachable Nodes In Subdivided Graph problem requires efficiently finding the reachable nodes using graph traversal a…

排序数组

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

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…

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.

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…

拼车

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

餐盘栈

Design a system that manages dinner plate stacks using stack-based state management, handling dynamic plate placement an…

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…

搜索推荐系统

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

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…

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…

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.

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…

3n 块披萨

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

最长快乐字符串

Solve the "Longest Happy String" problem using a greedy approach with validation of invariants for constructing the long…

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…

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.

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…

避免洪水泛滥

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

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…

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…

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…

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…

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…

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.

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…

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…

跳跃游戏 VI

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

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.

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…

移除石子的最大得分

Maximize the score in a solitaire game by optimally removing stones from three piles with a greedy approach.

车队 II

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

从第一个节点出发到最后一个节点的受限路径数

Solve the problem of finding the number of restricted paths in a weighted undirected graph, leveraging graph algorithms …

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 …

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 …

求出 MK 平均值

Find the MKAverage of a stream of integers using a queue-driven approach with efficient state management.

单线程 CPU

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

座位预约管理系统

Manage seat reservations efficiently using a design combining priority queue to always return the lowest available seat …

包含每个查询的最小区间

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

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.

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…

设计电影租借系统

Implement a movie rental system with efficient search, rent, drop, and report operations using arrays and hash lookups.

最小未被占据椅子的编号

Solve The Number of the Smallest Unoccupied Chair by sorting arrivals and managing freed seats before each new assignmen…

移除石子使总数最小

Minimize the total stones by repeatedly removing half from the largest pile using a greedy heap strategy.

找出数组中的第 K 大整数

This problem asks to find the kth largest integer in an array of string numbers, highlighting sorting and string-based c…

股票价格波动

Design an efficient algorithm for managing stock price fluctuations with incorrect and unordered data in a data stream.

两个最好的不重叠活动

Maximize the total value of at most two non-overlapping events using state transition dynamic programming efficiently.

找到和最大的长度为 K 的子序列

Pick the k largest values, then restore their original order to build the maximum-sum subsequence correctly.

序列顺序查询

Track rankings of locations with names and scores, adding new locations and retrieving top-ranked ones efficiently.

价格范围内最高排名的 K 样物品

Use BFS to rank reachable shop items by distance, price, row, and column, then return the best k coordinates.

删除元素后和的最小差值

Minimize the difference between sums after removing n elements from a 3n array by dividing the remaining elements into t…

构造限制重复的字符串

Construct a lexicographically largest string from a given string with no letter appearing more than a repeatLimit times …

将数组和减半的最少操作次数

Minimize operations to halve an array's sum using greedy choices and heap data structures.

按奇偶性交换后的最大数字

Maximize a number by swapping digits of the same parity using sorting and priority queue techniques efficiently.

K 次增加后的最大乘积

Maximize the product of an array after performing up to k increments using a greedy approach with heap optimization.

道路的最大总重要性

Assign unique values to cities to maximize the total importance of all roads using greedy selection based on city connec…

到达角落需要移除障碍物的最小数目

Find the minimum obstacles to remove in a 2D grid to reach the bottom-right corner using BFS graph traversal techniques.

最小差值平方和

Calculate the minimum sum of squared differences between two arrays using limited modifications and binary search techni…

装满杯子需要的最短总时长

Determine the minimum seconds to fill cups of cold, warm, and hot water using a greedy selection strategy and invariant …

无限集中的最小数字

Design a data structure to handle the smallest missing element in an infinite set, with the ability to add and remove el…

数位和相等数对的最大和

Find the maximum sum of two numbers with equal digit sums in a given array of positive integers.

裁剪数字后查询第 K 小的数字

Solve the Query Kth Smallest Trimmed Number problem by efficiently trimming and sorting strings in an array to answer qu…

使数组可以被整除的最少删除次数

Find the minimum number of deletions to make the smallest element in nums divide all elements of numsDivide.

设计数字容器系统

Learn to implement a Number Container System using hash tables and design techniques to efficiently track numbers and in…

设计食物评分系统

Design a food rating system that tracks and updates ratings of foods, finding the highest rated items by cuisine.

使数组中所有元素都等于零

Minimize operations to make all array elements zero by subtracting equal amounts in each operation.

找出数组的第 K 大和

Find the K-Sum of an Array requires computing the kth largest subsequence sum in an array using sorting and heap techniq…

预算内的最多机器人数目

Determine the maximum number of consecutive robots you can operate without exceeding a given budget using efficient bina…

会议室 III

Determine which meeting room holds the most meetings by simulating room assignments with precise time tracking.

将区间分为最少组数

Determine the minimum number of non-overlapping groups for a set of intervals using precise two-pointer scanning logic.

最长上传前缀

Calculate the longest continuous uploaded prefix in a video stream efficiently using a mix of binary search and data str…

下一个更大元素 IV

Find the second greater integer for each element in an array using binary search and monotonic stack techniques.

最流行的视频创作者

Identify the most popular video creator by summing views and selecting their top-viewed video with array and hash patter…

雇佣 K 位工人的总代价

Optimize the total cost of hiring exactly k workers using a two-pointer approach with invariant tracking and priority qu…

图中最大星和

Find the maximum star sum in a graph with specific node values and edges, using greedy algorithms to select the optimal …

删除每行中的最大值

Calculate the total of removed maximum values from each row of a matrix, iterating until all columns are deleted efficie…

矩阵查询可获得的最大分数

Solve the Maximum Number of Points From Grid Queries problem using two-pointer scanning and invariant tracking.

奖励最顶尖的 K 名学生

Calculate top K student scores by scanning reports and using hash tables for positive and negative word lookups efficien…

执行 K 次操作后的最大分数

Maximize your score by applying exactly k operations on an array using greedy selection and heap optimization techniques…

过桥的时间

Time to Cross a Bridge involves simulating worker movements using arrays and heaps to determine when the last worker cro…

最大子序列的分数

Maximize the score of a subsequence by selecting indices based on nums1 and nums2, using a greedy approach and sorting.

将珠子放入背包中

The "Put Marbles in Bags" problem challenges you to distribute marbles into bags for maximum score difference using gree…

从数量最多的堆取走礼物

Take Gifts From the Richest Pile uses a heap to simulate the process of taking gifts from the richest pile over a number…

在网格图中访问一个格子的最少时间

Compute the fastest path in a grid where each cell has a minimum time requirement using BFS and priority queue technique…

标记所有元素后数组的分数

The problem involves marking elements in an array and calculating the score based on adjacent elements.

老鼠和奶酪

In 'Mice and Cheese', you must maximize the total reward of two mice eating cheese while respecting their preferences an…

网格图中最少访问的格子数

Determine the minimum number of cells to visit in a grid using state transition dynamic programming and efficient traver…

设计可以求最短路径的图类

Implement a dynamic weighted directed graph with efficient shortest path queries and edge additions in real time.

前往目标的最小代价

Find the minimum cost path between two points, using special roads or direct moves in a 2D space.

矩阵中的和

Calculate the maximum score by repeatedly removing the largest elements from each row of a 2D matrix efficiently using s…

修改图中的边权

Modify Graph Edge Weights is a graph problem where you adjust edge weights to match a target shortest path distance.

不间断子数组

Count all continuous subarrays efficiently using sliding window with running max-min state tracking for array consistenc…

找出最安全路径

Find the Safest Path in a Grid uses binary search and BFS to maximize path safeness from thieves in a grid.

子序列最大优雅度

Maximize elegance of a k-length subsequence from a list of items with profits and categories.

购买物品的最大开销

Maximize spending by carefully choosing the right items across multiple shops over m * n days.

找到 Alice 和 Bob 可以相遇的建筑

Determine the leftmost building where Alice and Bob can meet using a binary search over valid move sequences.

购买水果需要的最少金币数

Calculate the minimum coins to buy fruits using state transition dynamic programming while handling rewards and purchase…

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 …

树中每个节点放置的金币数目

Determine the exact number of coins to place on each tree node using subtree cost products and DFS tracking.

最小数字游戏

The Minimum Number Game involves simulating moves by Alice and Bob on an array, sorting elements and appending them to a…

将数组分成最小总代价的子数组 II

This problem asks to divide an array into subarrays with a minimal cost and certain constraints on subarray positions.

标记所有下标的最早秒数 II

This problem asks to determine the earliest second at which all indices in an array can be marked using a sequence of op…

超过阈值的最少操作数 II

Calculate the fewest operations to make every array element exceed a threshold using a min-heap simulation strategy effi…

执行操作标记数组中的元素

Efficiently mark elements in an array based on queries using scanning plus hash lookup to track marked indices and compu…

替换字符串中的问号使分数最小

Minimize the cost of a string with '?' characters by replacing them with letters in lexicographical order while minimizi…

最高频率的 ID

Track the most frequent ID after each update in a dynamic collection of IDs with changing frequencies.

访问消失节点的最少时间

Determine the minimum time to visit each node in a disappearing-node graph using arrays, graphs, and priority queues eff…

最短路径中的边

Use two Dijkstra runs to mark exactly which edges can appear on at least one shortest path from 0 to n - 1.

删除星号以后字典序最小的字符串

Find the lexicographically smallest string by removing stars using stack-based state management and careful character se…

K 次乘运算后的最终数组 I

Solve the problem of determining the final state of an array after multiple multiplication operations using a priority q…

K 次乘运算后的最终数组 II

Optimize the final state of an array after performing k multiplication operations with priority queues.

第 K 近障碍物查询

Solve the K-th nearest obstacle query problem using array and heap (priority queue) techniques to find distances efficie…

穿越网格图的安全路径

Determine if you can safely traverse a binary grid from top-left to bottom-right using limited health points.

移山所需的最少秒数

Determine the minimum seconds required to reduce a mountain to zero height using simultaneous workers efficiently.

计算子数组的 x-sum I

Compute the x-sum of every subarray of length k efficiently using array scanning combined with hash lookup techniques.

计算子数组的 x-sum II

Calculate the x-sum for every k-length subarray using efficient array scanning and hash-based counting techniques.

到达最后一个房间的最少时间 I

Find Minimum Time to Reach Last Room I challenges you to determine the minimum time to travel in a dungeon with a grid l…

到达最后一个房间的最少时间 II

Calculate the minimum time to reach the last room in a grid with alternating move times using array and graph patterns.

零数组变换 III

Zero Array Transformation III requires removing the minimum number of queries to make all elements zero using greedy val…

使两个整数相等的数位操作

Transform n into m using allowed digit operations without creating primes, applying math and graph strategies efficientl…

设计任务管理器

Design a Task Manager that can efficiently handle task management operations such as adding, editing, executing, and rem…

提取至多 K 个元素的最大总和

Find the maximum sum by selecting at most k elements from a 2D matrix respecting per-row limits using a greedy strategy.

选出和最大的 K 个元素

Choose K Elements With Maximum Sum involves sorting and selecting elements based on a specific rule, applying array plus…

使 K 个子数组内元素相等的最少操作数

Compute the minimum operations to ensure at least k non-overlapping subarrays of size x have all equal elements efficien…

移除最小数对使数组有序 I

This problem asks for the minimum number of operations to make an array non-decreasing by removing pairs of elements.

移除最小数对使数组有序 II

The problem asks to find the minimum number of operations to make an array non-decreasing by removing pairs of elements.

选择不同 X 值三元组使 Y 值之和最大

Select three distinct x-values from arrays to maximize the sum of their corresponding y-values efficiently using hashing…

所有人渡河所需的最短时间

Find the minimum time to transport individuals across a river with dynamic environmental conditions and boat capacity.

有向图中到达终点的最少时间

The problem involves finding the minimum time to reach the destination in a directed graph with time-dependent edges.

电网维护

Determine which power stations remain connected after maintenance using array scanning and hash lookups to track compone…

恢复网络路径

Find the maximum recovery cost of valid paths in a directed acyclic graph where some nodes are offline.