Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, th…

A robot is located at the top-left corner of a m x n grid (marked ‘Start’ in t…

题目： There are two sorted arrays A and B of size m and n respectively. Find the median of the two sorted arrays…

There are N children standing in a line. Each child is assigned a rating value. You are giving candi…

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the value…

Given a string containing just the characters '(', ')', '{', '}', '[' and '…

Given a sorted array of integers, find the starting and ending position of a given target value. Your algorith…

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

Given n, generate all structurally unique BST’s (binary search trees) that store values 1…

Given an array and a value, remove all instances of that value in place and return the new length. The order o…

题目： Reverse digits of an integer. Example1: x = 123, return 321Example2: x = -123, return -321 click…

wo elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its struct…