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…