原文链接: https://leetcode-cn.com/problems/3sum-with-multiplicity 英文原文Given an integer array arr, and an integer target, return the number of tuples i, j, k such that i < j < k and arr[i] + arr[j] + arr[k] == target. As the answer can be very large, retu…

原文链接: https://leetcode-cn.com/problems/minimize-malware-spread 英文原文You are given a network of n nodes represented as an n x n adjacency matrix graph, where the ith node is directly connected to the jth node if graph[i][j] == 1. Some nodes initial are…

原文链接: https://leetcode-cn.com/problems/long-pressed-name 英文原文Your friend is typing his name into a keyboard. Sometimes, when typing a character c, the key might get long pressed, and the character will be typed 1 or more times. You examine the typed …

原文链接: https://leetcode-cn.com/problems/flip-string-to-monotone-increasing 英文原文A binary string is monotone increasing if it consists of some number of 0's (possibly none), followed by some number of 1's (also possibly none). You are given a binary str…

原文链接: https://leetcode-cn.com/problems/three-equal-parts 英文原文You are given an array arr which consists of only zeros and ones, divide the array into three non-empty parts such that all of these parts represent the same binary value. If it is possible…

原文链接: https://leetcode-cn.com/problems/minimize-malware-spread-ii 英文原文You are given a network of n nodes represented as an n x n adjacency matrix graph, where the ith node is directly connected to the jth node if graph[i][j] == 1. Some nodes initial …

原文链接: https://leetcode-cn.com/problems/binary-subarrays-with-sum 英文原文Given a binary array nums and an integer goal, return the number of non-empty subarrays with a sum goal. A subarray is a contiguous part of the array. Example 1: Input: nums = [1,0,…

原文链接: https://leetcode-cn.com/problems/minimum-falling-path-sum 英文原文Given an n x n array of integers matrix, return the minimum sum of any falling path through matrix. A falling path starts at any element in the first row and chooses the element in t…

原文链接: https://leetcode-cn.com/problems/number-of-recent-calls 英文原文You have a RecentCounter class which counts the number of recent requests within a certain time frame. Implement the RecentCounter class: RecentCounter() Initializes the counter with z…

原文链接: https://leetcode-cn.com/problems/beautiful-array 英文原文An array nums of length n is beautiful if: nums is a permutation of the integers in the range [1, n]. For every 0 <= i < j < n, there is no index k with i < k < j where 2 * nums[k] == nums[i]…

原文链接: https://leetcode-cn.com/problems/shortest-bridge 英文原文You are given an n x n binary matrix grid where 1 represents land and 0 represents water. An island is a 4-directionally connected group of 1's not connected to any other 1's. There are exact…

原文链接: https://leetcode-cn.com/problems/knight-dialer 英文原文The chess knight has a unique movement, it may move two squares vertically and one square horizontally, or two squares horizontally and one square vertically (with both forming the shape of an …

原文链接: https://leetcode-cn.com/problems/stamping-the-sequence 英文原文You are given two strings stamp and target. Initially, there is a string s of length target.length with all s[i] == '?'. In one turn, you can place stamp over s and replace every letter…

原文链接: https://leetcode-cn.com/problems/reorder-data-in-log-files 英文原文You are given an array of logs. Each log is a space-delimited string of words, where the first word is the identifier. There are two types of logs: Letter-logs: All words (except th…

原文链接: https://leetcode-cn.com/problems/range-sum-of-bst 英文原文Given the root node of a binary search tree and two integers low and high, return the sum of values of all nodes with a value in the inclusive range [low, high]. Example 1: Input: root = [10…

原文链接: https://leetcode-cn.com/problems/minimum-area-rectangle 英文原文You are given an array of points in the X-Y plane points where points[i] = [xi, yi]. Return the minimum area of a rectangle formed from these points, with sides parallel to the X and Y…

原文链接: https://leetcode-cn.com/problems/valid-mountain-array 英文原文Given an array of integers arr, return true if and only if it is a valid mountain array. Recall that arr is a mountain array if and only if: arr.length >= 3 There exists some i with 0 < …

原文链接: https://leetcode-cn.com/problems/find-the-shortest-superstring 英文原文Given an array of strings words, return the smallest string that contains each string in words as a substring. If there are multiple valid strings of the smallest length, return…

原文链接: https://leetcode-cn.com/problems/di-string-match 英文原文A permutation perm of n + 1 integers of all the integers in the range [0, n] can be represented as a string s of length n where: s[i] == 'I' if perm[i] < perm[i + 1], and s[i] == 'D' if perm[…

原文链接: https://leetcode-cn.com/problems/delete-columns-to-make-sorted 英文原文You are given an array of n strings strs, all of the same length. The strings can be arranged such that there is one on each line, making a grid. For example, strs = ["abc", "bc…

原文链接: https://leetcode-cn.com/problems/minimum-increment-to-make-array-unique 英文原文You are given an integer array nums. In one move, you can pick an index i where 0 <= i < nums.length and increment nums[i] by 1. Return the minimum number of moves to m…

原文链接: https://leetcode-cn.com/problems/validate-stack-sequences 英文原文Given two integer arrays pushed and popped each with distinct values, return true if this could have been the result of a sequence of push and pop operations on an initially empty st…

原文链接: https://leetcode-cn.com/problems/most-stones-removed-with-same-row-or-column 英文原文On a 2D plane, we place n stones at some integer coordinate points. Each coordinate point may have at most one stone. A stone can be removed if it shares either th…

原文链接: https://leetcode-cn.com/problems/largest-time-for-given-digits 英文原文Given an array arr of 4 digits, find the latest 24-hour time that can be made using each digit exactly once. 24-hour times are formatted as "HH:MM", where HH is between 00 and 2…

原文链接: https://leetcode-cn.com/problems/bag-of-tokens 英文原文You have an initial power of power, an initial score of 0, and a bag of tokens where tokens[i] is the value of the ith token (0-indexed). Your goal is to maximize your total score by potentiall…

原文链接: https://leetcode-cn.com/problems/reveal-cards-in-increasing-order 英文原文You are given an integer array deck. There is a deck of cards where every card has a unique integer. The integer on the ith card is deck[i]. You can order the deck in any ord…

原文链接: https://leetcode-cn.com/problems/largest-component-size-by-common-factor 英文原文You are given an integer array of unique positive integers nums. Consider the following graph: There are nums.length nodes, labeled nums[0] to nums[nums.length - 1], T…

原文链接: https://leetcode-cn.com/problems/verifying-an-alien-dictionary 英文原文In an alien language, surprisingly, they also use English lowercase letters, but possibly in a different order. The order of the alphabet is some permutation of lowercase letter…

原文链接: https://leetcode-cn.com/problems/array-of-doubled-pairs 英文原文Given an integer array of even length arr, return true if it is possible to reorder arr such that arr[2 * i + 1] = 2 * arr[2 * i] for every 0 <= i < len(arr) / 2, or false otherwise. E…

原文链接: https://leetcode-cn.com/problems/delete-columns-to-make-sorted-ii 英文原文You are given an array of n strings strs, all of the same length. We may choose any deletion indices, and we delete all the characters in those indices for each string. For e…