题目： Given an array of integers, find two numbers such that they add up to a specific target number. The functi…

Given an unsorted integer array, find the first missing positive integer. For example, Given [1,2,0] …

Given a linked list, reverse the nodes of a linked list k at a time and return its modified list. If…

Given an array of integers, every element appears three times except for one. Find that single one. …

Given an array with n objects colored red, white or blue, sort them so that objects of the same colo…

Given a 2D board containing 'X' and 'O', capture all regions surrounded by 'X'. A region i…

Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on …

There are N gas stations along a circular route, where the amount of gas at station i is&n…

题目： Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hi…

Given a binary tree and a sum, find all root-to-leaf paths where each path’s sum equals the given sum. F…

Given a digit string, return all possible letter combinations that the number could represent. A mapping of di…

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.…