qibobo的专栏

Given a string, find the length of the longest substring without repeating characters.Examples:Given "abcabcbb", the answer is "abc", which the length is 3.Given "bbbbb", the answer is "

Given a linked list, remove the nth node from the end of list and return its head.For example, Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from the end, the

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.The brackets must close in the correct order, "()" and "()[]{}" are all va

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.直接上代码了。java/** * Definition for singly-linked list

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 exactly one solution.Example:Given nums =

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

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, given n = 3, a solution set is:[ "((()))", "(()())", "(())()", "()(())

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.Leetcode 21题是合并两个链表。合并K个链表的方法就是2的进一步。有两种方法：1 归并法。即每次链表数组中相邻的两个链表合并，结果为一个新的链表数组，重复之前的流程知道数组中只有一个元

Given a linked list, swap every two adjacent nodes and return its head.For example,Given 1->2->3->4, you should return the list as 2->1->4->3.Your algorithm should use only constant space. Y

Given a linked list, reverse the nodes of a linked list k at a time and return its modified list.If the number of nodes is not a multiple of k then left-out nodes in the end should remain as it is

Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target.Note: The solution

Given a digit string, return all possible letter combinations that the number could represent.A mapping of digit to letters (just like on the telephone buttons) is given below.Input:Di

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. You may assume that each input would have exact

There are two sorted arrays nums1 and nums2 of size m and n respectively.Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).Example 1:nums1 =

Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.本题是求一个字符串的最长的回文子串。

Reverse digits of an integer.Example1: x = 123, return 321Example2: x = -123, return -321click to show spoilers.Have you thought about this?Here are some good questions to ask before c

Determine whether an integer is a palindrome. Do this without extra space.click to show spoilers.Some hints:Could negative integers be palindromes? (ie, -1)If you are thinking of convertin

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 two endpoints of line i is at (i, ai) and (i, 0). Fin

Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from 1 to 3999.这道题基本没什么算法上的难点，就是需要知道罗马字母和整数的对应关系就行了。1~9: {"I", "II", "III", "IV", "V", "VI", "V

Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.这道题和12题正好相反，但是要比12题难一点。最重要的还是要熟悉对应表。1~9: {"I", "II", "III", "IV", "V", "VI", "VI

Write a function to find the longest common prefix string amongst an array of strings.比较简单，直接上代码。java代码public class Solution { public String longestCommonPrefix(String[] strs) { if(s

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.Note: The solution set must not contain

Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.java代码public class Solution { public int strStr(String