原文链接: https://leetcode-cn.com/problems/number-of-enclaves 英文原文You are given an m x n binary matrix grid, where 0 represents a sea cell and 1 represents a land cell. A move consists of walking from one land cell to another adjacent (4-directionally) l…

原文链接: https://leetcode-cn.com/problems/remove-outermost-parentheses 英文原文A valid parentheses string is either empty "", "(" + A + ")", or A + B, where A and B are valid parentheses strings, and + represents string concatenation. For example, "", "()",…

原文链接: https://leetcode-cn.com/problems/sum-of-root-to-leaf-binary-numbers 英文原文You are given the root of a binary tree where each node has a value 0 or 1. Each root-to-leaf path represents a binary number starting with the most significant bit. For ex…

原文链接: https://leetcode-cn.com/problems/video-stitching 英文原文You are given a series of video clips from a sporting event that lasted time seconds. These video clips can be overlapping with each other and have varying lengths. Each video clip is describ…

原文链接: https://leetcode-cn.com/problems/divisor-game 英文原文Alice and Bob take turns playing a game, with Alice starting first. Initially, there is a number n on the chalkboard. On each player's turn, that player makes a move consisting of: Choosing any …

原文链接: https://leetcode-cn.com/problems/longest-arithmetic-subsequence 英文原文Given an array nums of integers, return the length of the longest arithmetic subsequence in nums. Recall that a subsequence of an array nums is a list nums[i1], nums[i2], ..., …

原文链接: https://leetcode-cn.com/problems/maximum-difference-between-node-and-ancestor 英文原文Given the root of a binary tree, find the maximum value v for which there exist different nodes a and b where v = |a.val - b.val| and a is an ancestor of b. A nod…

原文链接: https://leetcode-cn.com/problems/recover-a-tree-from-preorder-traversal 英文原文We run a preorder depth-first search (DFS) on the root of a binary tree. At each node in this traversal, we output D dashes (where D is the depth of this node), then we…

原文链接: https://leetcode-cn.com/problems/matrix-cells-in-distance-order 英文原文You are given four integers row, cols, rCenter, and cCenter. There is a rows x cols matrix and you are on the cell with the coordinates (rCenter, cCenter). Return the coordinat…

原文链接: https://leetcode-cn.com/problems/two-city-scheduling 英文原文A company is planning to interview 2n people. Given the array costs where costs[i] = [aCosti, bCosti], the cost of flying the ith person to city a is aCosti, and the cost of flying the it…

原文链接: https://leetcode-cn.com/problems/stream-of-characters 英文原文Design an algorithm that accepts a stream of characters and checks if a suffix of these characters is a string of a given array of strings words. For example, if words = ["abc", "xyz"] a…

原文链接: https://leetcode-cn.com/problems/maximum-sum-of-two-non-overlapping-subarrays 英文原文Given an integer array nums and two integers firstLen and secondLen, return the maximum sum of elements in two non-overlapping subarrays with lengths firstLen and…

原文链接: https://leetcode-cn.com/problems/moving-stones-until-consecutive 英文原文There are three stones in different positions on the X-axis. You are given three integers a, b, and c, the positions of the stones. In one move, you pick up a stone at an endp…

原文链接: https://leetcode-cn.com/problems/coloring-a-border 英文原文You are given an m x n integer matrix grid, and three integers row, col, and color. Each value in the grid represents the color of the grid square at that location. Two squares belong to th…

原文链接: https://leetcode-cn.com/problems/uncrossed-lines 英文原文You are given two integer arrays nums1 and nums2. We write the integers of nums1 and nums2 (in the order they are given) on two separate horizontal lines. We may draw connecting lines: a stra…

原文链接: https://leetcode-cn.com/problems/escape-a-large-maze 英文原文There is a 1 million by 1 million grid on an XY-plane, and the coordinates of each grid square are (x, y). We start at the source = [sx, sy] square and want to reach the target = [tx, ty]…

原文链接: https://leetcode-cn.com/problems/minimum-score-triangulation-of-polygon 英文原文You have a convex n-sided polygon where each vertex has an integer value. You are given an integer array values where values[i] is the value of the ith vertex (i.e., cl…

原文链接: https://leetcode-cn.com/problems/find-words-that-can-be-formed-by-characters 英文原文You are given an array of strings words and a string chars. A string is good if it can be formed by characters from chars (each character can only be used once). R…

原文链接: https://leetcode-cn.com/problems/moving-stones-until-consecutive-ii 英文原文There are some stones in different positions on the X-axis. You are given an integer array stones, the positions of the stones. Call a stone an endpoint stone if it has the…

原文链接: https://leetcode-cn.com/problems/binary-search-tree-to-greater-sum-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 ke…

原文链接: https://leetcode-cn.com/problems/maximum-level-sum-of-a-binary-tree 英文原文Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on. Return the smallest level x such that the sum of all the values of n…

原文链接: https://leetcode-cn.com/problems/as-far-from-land-as-possible 英文原文Given an n x n grid containing only values 0 and 1, where 0 represents water and 1 represents land, find a water cell such that its distance to the nearest land cell is maximized…

原文链接: https://leetcode-cn.com/problems/robot-bounded-in-circle 英文原文On an infinite plane, a robot initially stands at (0, 0) and faces north. The robot can receive one of three instructions: "G": go straight 1 unit; "L": turn 90 degrees to the left; "…

原文链接: https://leetcode-cn.com/problems/flower-planting-with-no-adjacent 英文原文You have n gardens, labeled from 1 to n, and an array paths where paths[i] = [xi, yi] describes a bidirectional path between garden xi to garden yi. In each garden, you want …

原文链接: https://leetcode-cn.com/problems/partition-array-for-maximum-sum 英文原文Given an integer array arr, partition the array into (contiguous) subarrays of length at most k. After partitioning, each subarray has their values changed to become the maxim…

原文链接: https://leetcode-cn.com/problems/longest-duplicate-substring 英文原文Given a string s, consider all duplicated substrings: (contiguous) substrings of s that occur 2 or more times. The occurrences may overlap. Return any duplicated substring that ha…

原文链接: https://leetcode-cn.com/problems/last-stone-weight 英文原文You are given an array of integers stones where stones[i] is the weight of the ith stone. We are playing a game with the stones. On each turn, we choose the heaviest two stones and smash th…

原文链接: https://leetcode-cn.com/problems/remove-all-adjacent-duplicates-in-string 英文原文You are given a string s consisting of lowercase English letters. A duplicate removal consists of choosing two adjacent and equal letters and removing them. We repeat…

原文链接: https://leetcode-cn.com/problems/longest-string-chain 英文原文You are given an array of words where each word consists of lowercase English letters. wordA is a predecessor of wordB if and only if we can insert exactly one letter anywhere in wordA w…

原文链接: https://leetcode-cn.com/problems/last-stone-weight-ii 英文原文You are given an array of integers stones where stones[i] is the weight of the ith stone. We are playing a game with the stones. On each turn, we choose any two stones and smash them tog…