If the correct value is out of the range of representable values, INT_MAX (2147483647) or INT_MIN (-2147483648) is returned.

A message containing letters from A-Z is being encoded to numbers using the following mapping:

Compare two strings A and B, determine whether A contains all of the characters in B.

Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target?

Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers.

Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.

The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.

Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.

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

Suppose a sorted array is rotated at some pivot unknown to you beforehand.

Given two sorted integer arrays A and B, merge B into A as one sorted array.

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

Given a binary tree, return the preorder traversal of its nodes' values.

Given a binary tree, return the inorder traversal of its nodes' values.

Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level and alternate between).

Given preorder and inorder traversal of a tree, construct the binary tree.

Given a binary search tree and a new tree node, insert the node into the tree. You should keep the tree still be a valid binary search tree.Given a unsorted array with integers, find the median of it.

Given a binary search tree and a new tree node, insert the node into the tree. You should keep the tree still be a valid binary search tree.

Given 2*n + 1 numbers, every numbers occurs twice except one, find it.

Given 2*n + 2 numbers, every numbers occurs twice except two, find them.

Given a root of Binary Search Tree with unique value for each node. Remove the node with given value. If there is no such a node with given value in the binary search tree, do nothing. You should keep the tree still a binary search tree after removal.

Design an iterator over a binary search tree with the following rules:

Given the root and two nodes in a Binary Tree. Find the lowest common ancestor(LCA) of the two nodes.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.

Problem Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. Example Given the below binary tree: {代码...} return 6. Note 调用helper函数更新路径和的最大值res，而helper函数本身需要递归，返回的是单边路径和single。这里需要注意：对于拱形路径和arch，从左...

The thief has found himself a new place for his thievery again. There is only one entrance to this area, called the "root." Besides the root, each house has one and only one parent house. After a tour, the smart thief realized that "all houses in this place forms a binary tree". It will automatic...

After robbing those houses on that street, the thief has found himself a new place for his thievery so that he will not get too much attention. This time, all houses at this place are arranged in a circle. That means the first house is the neighbor of the last one. Meanwhile, the security system ...

Given a binary tree, determine if it is a valid binary search tree (BST).

Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.