5. Longest Palindromic Substring
来源:互联网 发布:淘宝客佣金设置 编辑:程序博客网 时间:2024/05/29 03:15
背景
“回文”是指正读反读都能读通的句子,它是古今中外都有的一种修辞方式和文字游戏,如“我为人人,人人为我”等。在数学中也有这样一类数字有这样的特征,成为回文数(palindrome number)。
设n是一任意自然数。若将n的各位数字反向排列所得自然数n1与n相等,则称n为一回文数。例如,若n=1234321,则称n为一回文数;但若n=1234567,则n不是回文数。
注意:
1. 偶数个的数字也有回文数124421
2. 小数没有回文数
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”
Output: “bab”
Note: “aba” is also a valid answer.
Example:
Input: “cbbd”
Output: “bb”
代码实现
public string LongestPalindrome(string s) { //considering: adccbaabc. we get the palindrome "cc" and "cbaabc" //How do we get the "cbaabc"? //first k points to second 'a' and j points to first 'b' by such logics: //while (k < s.Length - 1 && s[k + 1] == s[k]) // ++k; // moves when happing duplicate characters. //then we compare the k+1 index to j-1 index, such s[k+1]== s[j-1] is ok. It's finished by expand logics: //while (k < s.Length - 1 && j >= 1 && s[k + 1] == s[j - 1]) //{ // ++k; // --j; //} if (s.Length== 0 || s.Length==1) return s; int i=0, minstart = 0, maxlen = 1; while(i<s.Length){ if (s.Length - i <= maxlen / 2) break; int j = i, k = i; while (k < s.Length - 1 && s[k + 1] == s[k]) ++k; i = k + 1; while (k < s.Length - 1 && j >= 1 && s[k + 1] == s[j - 1]) { ++k; --j; } int newlen = k - j + 1; if (newlen > maxlen){ minstart = j; maxlen = newlen; } } return s.Substring(minstart, maxlen); }
题库
Leetcode算法题目解决方案每天更新在github库中,欢迎感兴趣的朋友加入进来,也欢迎star,或pull request。https://github.com/jackzhenguo/leetcode-csharp
完成题目索引
http://blog.csdn.net/daigualu/article/details/73008186
阅读全文
2 0
- 5.Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5.Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5.Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5.Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- 5. Longest Palindromic Substring
- c#调试输出和日志程序
- 未来 5年 最赚钱的行业 -马云篇
- myeclipse2014安装SVN插件,SVN插件安装
- 关于Centos 7设置host,并配置ssh免登录
- Coderforces Football
- 5. Longest Palindromic Substring
- 如何把直播嵌入微信公众账号
- 刷清橙OJ--A1061.求因子个数
- 刘强东:未来5年高利润高市场增长的五大行业,你有意向从事吗?
- 关于代理服务器与NAT
- ZooKeeper 基本介绍
- jq阻止页面事件及恢复的方法
- 探讨!自媒体的推荐机制提高百家号阅读收益方法!
- SaltStack实战之配置管理-YAML编写技巧