//Given an array of intervals where intervals[i] = [starti, endi], merge all ove //rlapping intervals, and return an arr

//You are given an integer array nums. You are initially positioned at the array //'s first index, and each element in t

//Given an m x n matrix, return all elements of the matrix in spiral order. // // // Example 1: // // //Input: matrix =

//Given an integer array nums, find the contiguous subarray (containing at least // one number) which has the largest su

//Implement pow(x, n), which calculates x raised to the power n (i.e., xn). // // // Example 1: // // //Input: x = 2

//Given an array of strings strs, group the anagrams together. You can return th //e answer in any order. // // An Anag

//You are given an n x n 2D matrix representing an image, rotate the image by 90 // degrees (clockwise). // // You have

//Given an array nums of distinct integers, return all the possible permutations //. You can return the answer in any or

//Given an input string (s) and a pattern (p), implement wildcard pattern matchi //ng with support for '?' and '*' where

//Given n non-negative integers representing an elevation map where the width of // each bar is 1, compute how much wate

//Given an unsorted integer array nums, return the smallest missing positive int //eger. // // You must implement an al

//The count-and-say sequence is a sequence of digit strings defined by the recur //sive formula: // // // countAndSay(