Given a string array words, return an array of all characters that show up in all strings within the words (including duplicates). You may return the answer in any order. Example 1:Input: words =

You are given an 8 x 8 matrix representing a chessboard. There is exactly one white rook represented by ‘R’, some number of white bishops ‘B’, and some number of black pawns ‘p’. Empty squares are rep

Given two integers left and right that represent the range [left, right], return the bitwise AND of all numbers in this range, inclusive. Example 1:Input: left = 5, right = 7Output: 4 Exampl

Given an input string, reverse the string word by word. Example 1:Input: “the sky is blue”Output: “blue is sky the” Example 2:Input: “ hello world! “Output: “world! hello”Explanation: Your reversed

Given a non-empty, singly linked list with head node head, return a middle node of linked list. If there are two middle nodes, return the second middle node. Example 1:Input: [1,2,3,4,5]Output: Node 3

Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order. A mapping of digits to letters (just like

Given the root of a complete binary tree, return the number of the nodes in the tree. According to Wikipedia, every level, except possibly the last, is completely filled in a complete binary tree, and

Given the root of a binary search tree, and an integer k, return the kth smallest value (1-indexed) of all the values of the nodes in the tree. Example 1:Input: root = [3,1,4,null,2], k = 1O

Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is guaranteed to

Given a string s which consists of lowercase or uppercase letters, return the length of the longest palindrome that can be built with those letters. Letters are case sensitive, for example, “Aa” is no