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Given two arrays, write a function to compute their intersection. Example: Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2]. Note: Each element in the result must be unique. The result can b

Given two strings s and t which consist of only lowercase letters. String t is generated by random shuffling string s and then add one more letter at a random position. Find the letter that was added

Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with those letters. This is case sensitive, for example “Aa” is not consid

Invert a binary tree. 4 / \ 2 7 / \ / \ 1 3 6 9 to 4 / \ 7 2 / \ / \ 9 6 3 1 题意： 翻转二叉树，属于二叉树基本操作。 不过关于这道题是关于Max Howell大神的一次求职，其来自于Twitter的转播“

Given an array nums, write a function to move all 0’s to the end of it while maintaining the relative order of the non-zero elements. For example, given nums = [0, 1, 0, 3, 12], after calling your fun

Find the sum of all left leaves in a given binary tree. Example: 3 / \ 9 20 / \ 15 7 There are two left leaves in the binary tree, with values 9 and 15 respectively.

Given
 an 
arbitrary
 ransom
 note
 string 
and 
another 
string 
containing 
letters from
 all 
the 
magazines,
 write 
a 
function 
that 
will 
return 
true 
if 
the 
ransom 
 note 
can 
be 
construc

Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node with value 3,

面试或笔试中，多次遇到以下4个关于排雷组合的手撕算法，这里做个笔记，方法日后查阅： 1. 无重复元素的数组，求全排列； 2. 有重复元素的数组，求全排列； 3. 无重复元素的数组，求组合【子集】； 4. 有重复元素的数组，求组合； 以上四类题，可以用统一的模板实现，如下所示：/* *【组合&&排列】 *把一个数组里的数组合全部列出，比如1和2列出来为1,2,12,21. *这

Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. 题意：求一个二叉树的深度（即从根节点到最远叶子节点的距离） 分析：学过数据结

Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digi

Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical and the nodes have the same value. 题意： 给出两颗二叉树，判断

Related to question Excel Sheet Column Title Given a column title as appear in an Excel sheet, return its corresponding column number. For example: A -> 1 B -> 2 C -> 3 … Z -

Write a function that takes a string as input and reverse only the vowels of a string. Example 1: Given s = “hello”, return “holle”. Example 2: Given s = “leetcode”, return “leotcede”. Note: The

You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a link

Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.Example:Given a = 1 and b = 2, return 3.分析:首先不能使用加减运算,那只有位运算了;17+5=22的过程,先不考虑进位,即17+05=

Write a function that takes a string as input and returns the string reversed.Example:Given s = "hello", return "olleh".

You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 stones. The one who removes the last stone will be the

Given an array of integers, every element appears twice except for one. Find that single one. Note: our algorithm should have a linear runtime complexity. Could you implement it without using extra

首先，感谢原博主的文章http://blog.youkuaiyun.com/javyzheng/article/details/41041667题目： 把一个数组里的数的组合全部列出，比如1和2列来为1,2,12,21. 分析： 这道题有多种扩展， 1，没有重复元素的数的组合（包括子集的全排列）； 2，有重复元素的数的组合； 3，没有重复元素的数的全排列； 4，有重复元素的数的全排列。1，没有重复