Given the root of a binary tree and an integer targetSum, return the number of paths where the sum of the values along the path equals targetSum. The path does not need to start or end at the root or

Let’s play the minesweeper game (Wikipedia, online game)! You are given an m x n char matrix board representing the game board where: ‘M’ represents an unrevealed mine,‘E’ represents an unrevealed emp

There is an m x n rectangular island that borders both the Pacific Ocean and Atlantic Ocean. The Pacific Ocean touches the island’s left and top edges, and the Atlantic Ocean touches the island’s righ

Given an m x n integers matrix, return the length of the longest increasing path in matrix. From each cell, you can either move in four directions: left, right, up, or down. You may not move diagonall

Given a string s and an integer k, return the number of substrings in s of length k with no repeated characters. Example 1:Input: s = “havefunonleetcode”, k = 5Output: 6Explanation: There ar

You are visiting a farm that has a single row of fruit trees arranged from left to right. The trees are represented by an integer array fruits where fruits[i] is the type of fruit the ith tree produce

There is an undirected graph with n nodes, where each node is numbered between 0 and n - 1. You are given a 2D array graph, where graph[u] is an array of nodes that node u is adjacent to. More formall

Given an array of integers nums, return the number of good pairs. A pair (i, j) is called good if nums[i] == nums[j] and i < j. Example 1:Input: nums = [1,2,3,1,1,3]Output: 4Explanat

You are given a doubly linked list, which contains nodes that have a next pointer, a previous pointer, and an additional child pointer. This child pointer may or may not point to a separate doubly lin

You are given a string s. We want to partition the string into as many parts as possible so that each letter appears in at most one part. Note that the partition is done so that after concatenating al