摘要：Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string. If the last word 阅读全文

摘要：Find the contiguous subarray within an array (containing at least one number) which has the largest sum. For example, given the array [-2,1,-3,4,-1,2, 阅读全文

摘要：The count-and-say sequence is the sequence of integers with the first five terms as following: 1 is read off as "one 1" or 11.11 is read off as "two 1 阅读全文

摘要：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 or 阅读全文

摘要：Given an array and a value, remove all instances of that value in-place and return the new length. Do not allocate extra space for another array, you 阅读全文

摘要：Given a sorted array, remove the duplicates in-place such that each element appear only once and return the new length. Do not allocate extra space fo 阅读全文

摘要：Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists. Example: 阅读全文

摘要：parentheses:括号 Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets mus 阅读全文

摘要：Write a function to find the longest common prefix string amongst an array of strings. 找出所有字符串中的共同字符串前缀。 方法一：让第一个字符串作为基准，遍历该字符串，依次将该字符串中的每个字符跟其他所有字符串相 阅读全文

摘要：Determine whether an integer is a palindrome. Do this without extra space. Some hints: Could negative integers be palindromes? (ie, -1) If you are thi 阅读全文

摘要：Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have ex 阅读全文

摘要：Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array. Example 1: 还是应用广度优先遍历（BFS），然后计算每一层的和就行 阅读全文

摘要：Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (an, bn) which makes sum of 阅读全文

摘要：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: 阅读全文

摘要：We have two special characters. The first character can be represented by one bit 0. The second character can be represented by two bits (10 or 11). N 阅读全文

摘要：题目： Given n non-negative integers a1 , a2 , ..., an , where each represents a point at coordinate (i, ai ). n vertical lines are drawn such that the t 阅读全文

摘要：Given a linked list, determine if it has a cycle in it. Follow up:Can you solve it without using extra space? 不使用额外空间：这里没有实例化一个对象，只是引用对象，所以不会开辟新内存空间 用 阅读全文

摘要：题目： Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321 Have you thought about this? Here are some good questi 阅读全文

摘要：Given an array of integers, every element appears twice except for one. Find that single one. Note: Your algorithm should have a linear runtime comple 阅读全文

摘要：题目： Say you have an array for which the i th element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may c 阅读全文