原文链接: https://leetcode-cn.com/problems/convert-bst-to-greater-tree 英文原文Given the root of a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus the sum of all keys greater …

原文链接: https://leetcode-cn.com/problems/minimum-time-difference 英文原文Given a list of 24-hour clock time points in "HH:MM" format, return the minimum minutes difference between any two time-points in the list. Example 1: Input: timePoints = ["23:59","00…

原文链接: https://leetcode-cn.com/problems/single-element-in-a-sorted-array 英文原文You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once. Return the single eleme…

原文链接: https://leetcode-cn.com/problems/reverse-string-ii 英文原文Given a string s and an integer k, reverse the first k characters for every 2k characters counting from the start of the string. If there are fewer than k characters left, reverse all of th…

原文链接: https://leetcode-cn.com/problems/01-matrix 英文原文Given an m x n binary matrix mat, return the distance of the nearest 0 for each cell. The distance between two adjacent cells is 1. Example 1: Input: mat = [[0,0,0],[0,1,0],[0,0,0]] Output: [[0,0,0…

原文链接: https://leetcode-cn.com/problems/diameter-of-binary-tree 英文原文Given the root of a binary tree, return the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This p…

原文链接: https://leetcode-cn.com/problems/remove-boxes 英文原文You are given several boxes with different colors represented by different positive numbers. You may experience several rounds to remove boxes until there is no box left. Each time you can choos…

原文链接: https://leetcode-cn.com/problems/number-of-provinces 英文原文There are n cities. Some of them are connected, while some are not. If city a is connected directly with city b, and city b is connected directly with city c, then city a is connected ind…

原文链接: https://leetcode-cn.com/problems/student-attendance-record-i 英文原文You are given a string s representing an attendance record for a student where each character signifies whether the student was absent, late, or present on that day. The record on…

原文链接: https://leetcode-cn.com/problems/student-attendance-record-ii 英文原文An attendance record for a student can be represented as a string where each character signifies whether the student was absent, late, or present on that day. The record only con…

原文链接: https://leetcode-cn.com/problems/optimal-division 英文原文You are given an integer array nums. The adjacent integers in nums will perform the float division. For example, for nums = [2,3,4], we will evaluate the expression "2/3/4". However, you can…

原文链接: https://leetcode-cn.com/problems/brick-wall 英文原文There is a rectangular brick wall in front of you with n rows of bricks. The ith row has some number of bricks each of the same height (i.e., one unit) but they can be of different widths. The tot…

原文链接: https://leetcode-cn.com/problems/next-greater-element-iii 英文原文Given a positive integer n, find the smallest integer which has exactly the same digits existing in the integer n and is greater in value than n. If no such positive integer exists, …

原文链接: https://leetcode-cn.com/problems/reverse-words-in-a-string-iii 英文原文Given a string s, reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. Example 1: Input: s = "Let's take Leet…

原文链接: https://leetcode-cn.com/problems/subarray-sum-equals-k 英文原文Given an array of integers nums and an integer k, return the total number of continuous subarrays whose sum equals to k. Example 1: Input: nums = [1,1,1], k = 2 Output: 2 Example 2: Inp…

原文链接: https://leetcode-cn.com/problems/array-partition-i 英文原文Given an integer array nums of 2n integers, group these integers into n pairs (a1, b1), (a2, b2), ..., (an, bn) such that the sum of min(ai, bi) for all i is maximized. Return the maximized…

原文链接: https://leetcode-cn.com/problems/find-the-closest-palindrome 英文原文Given a string n representing an integer, return the closest integer (not including itself), which is a palindrome. If there is a tie, return the smaller one. The closest is defin…

原文链接: https://leetcode-cn.com/problems/binary-tree-tilt 英文原文Given the root of a binary tree, return the sum of every tree node's tilt. The tilt of a tree node is the absolute difference between the sum of all left subtree node values and all right su…

原文链接: https://leetcode-cn.com/problems/array-nesting 英文原文You are given an integer array nums of length n where nums is a permutation of the numbers in the range [0, n - 1]. You should build a set s[k] = {nums[k], nums[nums[k]], nums[nums[nums[k]]], .…

原文链接: https://leetcode-cn.com/problems/reshape-the-matrix 英文原文In MATLAB, there is a handy function called reshape which can reshape an m x n matrix into a new one with a different size r x c keeping its original data. You are given an m x n matrix ma…

原文链接: https://leetcode-cn.com/problems/permutation-in-string 英文原文Given two strings s1 and s2, return true if s2 contains a permutation of s1, or false otherwise. In other words, return true if one of s1's permutations is the substring of s2. Example …

原文链接: https://leetcode-cn.com/problems/subtree-of-another-tree 英文原文Given the roots of two binary trees root and subRoot, return true if there is a subtree of root with the same structure and node values of subRoot and false otherwise. A subtree of a …

原文链接: https://leetcode-cn.com/problems/distribute-candies 英文原文Alice has n candies, where the ith candy is of type candyType[i]. Alice noticed that she started to gain weight, so she visited a doctor. The doctor advised Alice to only eat n / 2 of the …

原文链接: https://leetcode-cn.com/problems/out-of-boundary-paths 英文原文There is an m x n grid with a ball. The ball is initially at the position [startRow, startColumn]. You are allowed to move the ball to one of the four adjacent cells in the grid (possib…

原文链接: https://leetcode-cn.com/problems/shortest-unsorted-continuous-subarray 英文原文Given an integer array nums, you need to find one continuous subarray that if you only sort this subarray in ascending order, then the whole array will be sorted in asce…

原文链接: https://leetcode-cn.com/problems/delete-operation-for-two-strings 英文原文Given two strings word1 and word2, return the minimum number of steps required to make word1 and word2 the same. In one step, you can delete exactly one character in either s…

原文链接: https://leetcode-cn.com/problems/erect-the-fence 英文原文You are given an array trees where trees[i] = [xi, yi] represents the location of a tree in the garden. You are asked to fence the entire garden using the minimum length of rope as it is expe…

原文链接: https://leetcode-cn.com/problems/tag-validator 英文原文Given a string representing a code snippet, implement a tag validator to parse the code and return whether it is valid. A code snippet is valid if all the following rules hold: The code must be…

原文链接: https://leetcode-cn.com/problems/valid-square 英文原文Given the coordinates of four points in 2D space p1, p2, p3 and p4, return true if the four points construct a square. The coordinate of a point pi is represented as [xi, yi]. The input is not g…

原文链接: https://leetcode-cn.com/problems/longest-harmonious-subsequence 英文原文We define a harmonious array as an array where the difference between its maximum value and its minimum value is exactly 1. Given an integer array nums, return the length of it…