Given an array of strings words, return the first palindromic string in the array. If there is no such string, return an empty string “”. A string is palindromic if it reads the same forward and backw

Given the root of a binary tree, replace the value of each node in the tree with the sum of all its cousins’ values. Two nodes of a binary tree are cousins if they have the same depth with different p

LCP 30. 魔塔游戏小扣当前位于魔塔游戏第一层，共有 N 个房间，编号为 0 ~ N-1。每个房间的补血道具/怪物对于血量影响记于数组 nums，其中正数表示道具补血数值，即血量增加对应数值；负数表示怪物造成伤害值，即血量减少对应数值；0 表示房间对血量无影响。 小扣初始血量为 1，且无上限。假定小扣原计划按房间编号升序访问所有房间补血/打怪，为保证血量始终为正值，小扣需对

You are playing the following Nim Game with your friend:Initially, there is a heap of stones on the table.You and your friend will alternate taking turns, and you go first.On each turn, the person who

You are given an integer array nums of size n and a positive integer k. Divide the array into one or more arrays of size 3 satisfying the following conditions: Each element of nums should be in exactl

You are given a 0-indexed integer array nums and an integer k. Return an integer that denotes the sum of elements in nums whose corresponding indices have exactly k set bits in their binary representa

You are given a 0-indexed array words consisting of distinct strings. The string words[i] can be paired with the string words[j] if: The string words[i] is equal to the reversed string of words[j].0 &

Given two string arrays words1 and words2, return the number of strings that appear exactly once in each of the two arrays. Example 1:Input: words1 = [“leetcode”,”is”,”amazing”,”as”,”is”], words2

You are given a string s consisting only of uppercase English letters. You can apply some operations to this string where, in one operation, you can remove any occurrence of one of the substrings “AB”

Given an integer array nums, return the greatest common divisor of the smallest number and largest number in nums. The greatest common divisor of two numbers is the largest positive integer that evenl