2209. Minimum White Tiles After Covering With Carpets

Problem You are given a 0-indexed binary string floor, which represents the colors of tiles on a floor: floor[i] = '0' denot...

hard

1728. Cat and Mouse II

Problem A game is played by a cat and a mouse named Cat and Mouse. The environment is represented by a grid of size rows x co...

hard

827. Making A Large Island

Problem You are given an n x n binary matrix grid. You are allowed to change at most one 0 to be 1. Return the size of the la...

hard

2412. Minimum Money Required Before Transactions

Problem You are given a 0-indexed 2D integer array transactions, where transactions[i] = [costᵢ, cashbackᵢ]. The array descri...

hard

2920. Maximum Points After Collecting Coins From All Nodes

Problem There exists an undirected tree rooted at node 0 with n nodes labeled from 0 to n - 1. You are given a 2D integer arr...

hard

2218. Maximum Value of K Coins From Piles

Problem There are n piles of coins on a table. Each pile consists of a positive number of coins of assorted denominations. In...

hard

42. Trapping Rain Water

Problem Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water ...

hard todo

1368. Minimum Cost to Make at Least One Valid Path in a Grid

Problem Given an m x n grid. Each cell of the grid has a sign pointing to the next cell you should visit if you are currently...

hard

3414. Maximum Score of Non-overlapping Intervals

Problem You are given a 2D integer array intervals, where intervals[i] = [lᵢ, rᵢ, weightᵢ]. Interval i starts at position lᵢ ...

hard

3298. Count Substrings That Can Be Rearranged to Contain a String II

Problem 跟 3297. Count Substrings That Can Be Rearranged to Contain a String I 一模一样,只是多了一个注意点: Note that the memory limits in ...

hard

3410. Maximize Subarray Sum After Removing All Occurrences of One Element

Problem You are given an integer array nums. You can do the following operation on the array at most once: Choose any intege...

hard

3045. Count Prefix and Suffix Pairs II

Problem 跟 3042. Count Prefix and Suffix Pairs I 一模一样,但单词数量从 50 提升到 10⁵,同时单词的长度也从 10 提升到 10⁵。 https://leetcode.com/problems/co...

hard

3395. Subsequences with a Unique Middle Mode I

Problem 唯一中间众数子序列。 Given an integer array nums, find the number of subsequences of size 5 of nums with a unique middle mode...

hard

3399. Smallest Substring With Identical Characters II

跟 3398. Smallest Substring With Identical Characters I 一模一样,只不过 s 的长度上限从 1000 增加到 10⁵。 https://leetcode.com/problems/smallest...

hard

3398. Smallest Substring With Identical Characters I

Problem You are given a binary string s of length n and an integer numOps. You are allowed to perform the following operation...

hard

3405. Count the Number of Arrays with K Matching Adjacent Elements

Problem You are given three integers n, m, k. A good array arr of size n is defined as follows: Each element in arr is in th...

hard

732. My Calendar III

Problem A k-booking happens when k events have some non-empty intersection (i.e., there is some time that is common to all k ...

hard

730. Count Different Palindromic Subsequences

Problem Given a string s, return the number of different non-empty palindromic subsequences in s. Since the answer may be ver...

hard

913. Cat and Mouse

Problem A game on an undirected graph is played by two players, Mouse and Cat, who alternate turns. The graph is given as fol...

hard

321. Create Maximum Number

Problem You are given two integer arrays nums1 and nums2 of lengths m and n respectively. nums1 and nums2 represent the digit...

hard todo

843. Guess the Word

Problem You are given an array of unique strings words where words[i] is six letters long. One word of words was chosen as a ...

hard

1639. Number of Ways to Form a Target String Given a Dictionary

Problem You are given a list of strings of the same length words and a string target. Your task is to form target using the g...

hard

1206. Design Skiplist

Problem Design a Skiplist without using any built-in libraries. A skiplist is a data structure that takes O(log(n)) time to a...

hard

1250. Check If It Is a Good Array

Problem Given an array nums of positive integers. Your task is to select some subset of nums, multiply each element by an int...

hard

1298. Maximum Candies You Can Get from Boxes

Problem You have n boxes labeled from 0 to n - 1. You are given four arrays: status, candies, keys, and containedBoxes where:...

hard

689. Maximum Sum of 3 Non-Overlapping Subarrays

Problem Given an integer array nums and an integer k, find three non-overlapping subarrays of length k with maximum sum and r...

hard

2493. Divide Nodes Into the Maximum Number of Groups

Problem You are given a positive integer n representing the number of nodes in an undirected graph. The nodes are labeled fro...

hard

3219. Minimum Cost for Cutting Cake II

跟 3218. Minimum Cost for Cutting Cake I 一模一样,只不过 m 和 n 的量级从 20 增加到 10⁵,因此只能用 O(n log n) 贪心解法。 https://leetcode.cn/problems/mi...

hard

3218. Minimum Cost for Cutting Cake I

Problem There is an m x n cake that needs to be cut into 1 x 1 pieces. You are given integers m, n, and two arrays: horizont...

medium hard

2360. Longest Cycle in a Graph

Problem You are given a directed graph of n nodes numbered from 0 to n - 1, where each node has at most one outgoing edge. Th...

hard

2608. Shortest Cycle in a Graph

Problem There is a bi-directional graph with n vertices, where each vertex is labeled from 0 to n - 1. The edges in the graph...

hard

3203. Find Minimum Diameter After Merging Two Trees

Problem There exist two undirected trees with n and m nodes, numbered from 0 to n - 1 and from 0 to m - 1, respectively. You ...

hard
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