非常经典的题目,求字符串中的最长回文子串. (1)最朴素的解法 ---暴力 复杂度O(N³) 这也是最easy想到的方法.最外层循环枚举起点i,第二层循环从i+1開始向后枚举,第三层推断是不是回文串.最后取最长子串的返回. 代码比較简单,这里没有列出. (2)中心扩展法.复杂度O(N²) 枚举每个字符作为中心点向左右扩展. 可是这里要注意,对于每一次扩展要分奇偶两种情况. 否则可能会漏掉情况. 一发现不满足的情况立即break进行下一个中心字符的推断,代码例如以下: class Solution…

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. 这道题让我们求最长回文子串,首先说下什么是回文串,就是正读反读都一样的字符串,比如 "bob", "level", &q…

明天就要上课了,再过几天又要见班主任汇报项目进程了,什么都没做的我竟然有一种迷之淡定,大概是想体验一波熬夜修仙的快乐了.不管怎么说,每天还是要水一篇博文,写一个LeetCode的题才圆满. 题目:Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example:  Input: "babad" :  Out…

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example 1: Input: "babad" Output: "bab" Note: "aba" is also a valid answer. Example 2: Input: "cbbd"…

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. 题目的意思:输入一个字符串S,找出其最长回文串 用动态规划求解 决策变量:dp[i][j]记录从s[i]到s[j]组成的子串是否为回文. dp[i+1…

题目链接 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. 求字符串的最长回文子串 算法1:暴力解法,枚举所有子串,对每个子串判断是否为回文,复杂度为O(n^3) 算法2:删除暴力解法中有很多重复的判…

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. 方法: Manacher's algorithm,具体看这里http://leetcode.com/2011/11/longest-palindrom…

Longest Palindromic Substring: Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example: Input: "babad" Output: "bab" Note: "aba" is also a valid answer. Exam…

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. 动态规划 public class Solution { public String longestPalindrome(String s) { if…

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. 给定一个字符串S,找出当中的最长回文字符子串. 1.枚举全部子串,并推断是否是回文串同一时候记录最大长度.超时. //找出全部子串,并推断是否是回文串…

问题大意是在给定字符串中查找最长的回文子串,所谓的回文就是依据中间位置对称的字符串,比如abba,aba都是回文. 这个问题初一看,非常简单,但是会很快发现那些简单的思路都会带来O(n^3)级别的时间复杂度,n为传入字符串的实际长度.比如说下面的代码中的暴力枚举 for(i = 0; i < n; i = i + 1) for(j = i + 1; j < n; j = j + 1) ti = i, tj = j while(ti < tj && s[ti] == s[t…

class Solution(object): def longestPalindrome(self, s): """ :type s: str :rtype: str """ lenStr = len(s) if lenStr <= 0: return 0 maxLen = 0 tmpLen = 0 tmpRes = '' for i in range(0,lenStr): #odd numbers j=0 tmpLen=0 while…

class Solution { public: string longestPalindrome(string s) { int length=s.length(); ; ; ][]={false}; //初始化一个字符的回文串的动态状态 ;i<length;i++){ flag[i][i]=true; ){ maxlen=; start=i; } } //初始化状态矩阵,这里是长度为2的回文串 ;i<length-;i++){ ]){ flag[i][i+]=true; ){ maxlen…

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. 动态规划解法 O(n2) 超时 string longestPalindrome(string s) { if(s.empty()) return s…

题目来源:https://leetcode.com/problems/longest-palindromic-substring/ 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. 动态规划,类似于l…

一天一道LeetCode系列 (一)题目 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. 题意:求一个字符串的最长回文字串. (二)解题 1.中心扩展法 看到这个题首先想到的就是中心扩展法,遍历每一…

[Q4] 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)). You may assume nums1 and nums2 cannot be both empty. Example 1: nums1 = […

DP.KMP什么的都太高大上了.自己想了个朴素的遍历方法. [题目] 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. [思路](应该算是O(n)吧) 从中间向两端搜索.分别找到以每一个字母为中心的最…

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example 1: Input: "babad" Output: "bab" Note: "aba" is also a valid answer. Example 2: Input: "cbbd"…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 公众号:负雪明烛 本文关键词:最长回文子串,题解,leetcode, 力扣,python, C++, java 目录 题目描述 题目大意 解题方法 暴力遍历 动态规划 日期 题目地址:https://leetcode.com/problems/longest-palindromic-substring/description/ 题目描述 Given a string s, find t…

题目描述 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. 即给定一个字符串,求它的最长回文子串的长度(或者最长回文子串). 解法一 对于一个问题,一定可以找到一个傻的可爱的暴力解法,本题的暴力解法即…

写在前面:忍不住吐槽几句今天上海的天气,次奥,鞋子里都能养鱼了...裤子也全湿了,衣服也全湿了,关键是这天气还打空调,只能瑟瑟发抖祈祷不要感冒了.... 前后切了一百零几道leetcode的题(solution同步在github),主要是拣难度系数定为easy的水题做...好吧,这是第一道算法题.不知哪位大神说的,所有的语言都会过时,只有数据结构和算法才是永恒. 今天要重点讲的是优雅的Manacher算法,先来看这道题Longest Palindromic Substring,题目很简单,给你一…

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. 解题思路一: 暴力枚举 共N^2量级个子串(从下标零开始),每次检查需一个for循环,等于是3重for循环,时间复杂度O(n^3) 解题思路二: 动态…

Question: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.(给定一个字符串S,在S中找到最长的回文子字符串,假定最长的回文字符串长度是1000,并且在这个字符串中存在唯一的一个最长回文子字符串…

LeetCode(4) || Longest Palindromic Substring 与 Manacher 线性算法 题记 本文是LeetCode题库的第五题,没想到做这些题的速度会这么慢,工作之余全部耗在这上面了,只怪自己基础差.本文主要介绍使用Manacher线性算法来求解字符串的最长回文子字符串. 题目 Given a string S, find the longest palindromic substring in S. You may assume that the maxim…

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. 题目大意:给一个字符串S,存在唯一的最长的回文子串,求这个回文子串. 解题思路:首先这个题有O(n)的解,是在http://articles.leet…

题目 Given a string s,find the longest palindromic substring in S.You may assume  that the maximum length of S is 1000,and there exist one unique longest palindromic substring. 分析与解法 如果一段字符串是回文,那么以某个字符为中心的前缀和后缀都是相同的.例如,一段回文串"aba",以b为中心,它的前缀与后缀都是相同…

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com'https://oj.leetcode.com/problems/longest-palindromic-substring/ Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000,and there e…

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example 1:                             Input: "babad"                         Output: "bab"                      Note:…

Longest Palindromic Substring -- HARD 级别 Question SolutionGiven 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. 经典的DP题目. 主页君给出3种解…