leetcode409. Longest Palindrome
来源:互联网 发布:姚明对奥尼尔数据 编辑:程序博客网 时间:2024/06/06 01:48
409. Longest Palindrome
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 considered a palindrome here.
Note:
Assume the length of given string will not exceed 1,010.
Example:
Input:"abccccdd"Output:7Explanation:One longest palindrome that can be built is "dccaccd", whose length is 7.
解法一
数组记录每个字母对应出现的次数,如果是偶数,加上该字母的次数;如果是奇数,次数-1相加。
public class Solution { public int longestPalindrome(String s) { int[] alpha = new int[58]; int ret = 0; for (int i = 0; i < s.length(); i++) { alpha[s.charAt(i) - 'A']++; } for (int i = 0; i < alpha.length; i++) { if (alpha[i] > 0) { if (alpha[i] % 2 == 0) { ret += alpha[i]; } else if (alpha[i] > 2) { ret += alpha[i] - 1; } } } if (ret < s.length()) { ret++; } return ret; }}
解法二
解法一的优化版
public class Solution { public int longestPalindrome(String s) { int[] alpha = new int[58]; int ret = 0, kind = 0; for (int i = 0; i < s.length(); i++) { alpha[s.charAt(i) - 'A']++; } for (int i = 0; i < alpha.length; i++) { ret += (alpha[i] / 2) * 2; } return ret == s.length() ? ret : ret + 1; }}
解法三
set中添加元素,如果再次出现除掉该元素。
public class Solution { public int longestPalindrome(String s) { if (s == null || s.length() == 0) { return 0; } Set<Character> set = new HashSet<Character>(); int count = 0; for (int i = 0; i < s.length(); i++) { if (set.contains(s.charAt(i))) { set.remove(s.charAt(i)); count++; } else { set.add(s.charAt(i)); } } if (!set.isEmpty()) { return count * 2 + 1; } return count * 2; }}
阅读全文
0 0
- Leetcode409: Longest Palindrome
- Leetcode409. Longest Palindrome
- LeetCode409 Longest Palindrome
- leetcode409. Longest Palindrome
- LeetCode409. Longest Palindrome青春在飘逝
- leetcode409
- Longest Palindrome
- Longest Palindrome
- Longest Palindrome
- Longest Palindrome
- Longest Palindrome
- Longest Palindrome
- Longest Palindrome
- Longest Palindrome
- uva 11151 Longest Palindrome
- 11151 - Longest Palindrome
- UVa 11151 - Longest Palindrome
- longest Palindrome substring
- 图灵杯-第四届“图灵杯”NEUQ-ACM 程序设计竞赛-G-那么大奶牛之神
- java核心技术卷1内容总结
- 去百度面试运维开发
- PAT-A-1096. Consecutive Factors (20)
- (四)c++和JavaScript实现归并排序
- leetcode409. Longest Palindrome
- linux centos7 mysql无法远程连接解决办法
- 生产者消费者模型
- 322. Coin Change
- Arduino + AD9851 DDS信号模块 频率控制字和相位控制字写入
- pytorch 没有梯度
- 没事的时候,自己暗示自己
- python环境搭建-IDE
- 213.m1-至动画实现布局的显示与隐藏