LeetCode Palindrome Permutation
原题链接在这里:https://leetcode.com/problems/palindrome-permutation/
题目:
Given a string, determine if a permutation of the string could form a palindrome.
For example,"code"
-> False, "aab"
-> True, "carerac"
-> True.
题解:
看能否配对出现.
Time Complexity: O(n). Space: O(n).
AC Java:
public class Solution {
public boolean canPermutePalindrome(String s) {
if(s == null || s.length() <= 1){
return true;
}
HashSet<Character> hs = new HashSet<Character>();
for(int i = 0; i<s.length(); i++){
char c = s.charAt(i);
if(!hs.contains(c)){
hs.add(c);
}else{
hs.remove(c);
}
}
return hs.size() == 0 || hs.size() == 1;
}
}
可以用bitMap
Time Complexity: O(n). Space: O(256).
public class Solution {
public boolean canPermutePalindrome(String s) {
if(s == null || s.length() <= 1){
return true;
}
int [] map = new int[256];
for(int i = 0; i<s.length(); i++){
map[s.charAt(i)]++;
}
int count = 0;
for(int i = 0; i<256; i++){
if(count == 0 && map[i]%2 == 1){ //第一次出现frequency为奇数的char
count++;
}else if(map[i] % 2 == 1){ //第二次出现frequency为奇数的char
return false;
}
}
return true;
}
}
LeetCode Palindrome Permutation的更多相关文章
- [LeetCode] Palindrome Permutation II 回文全排列之二
Given a string s, return all the palindromic permutations (without duplicates) of it. Return an empt ...
- [LeetCode] Palindrome Permutation 回文全排列
Given a string, determine if a permutation of the string could form a palindrome. For example," ...
- LeetCode Palindrome Permutation II
原题链接在这里:https://leetcode.com/problems/palindrome-permutation-ii/ 题目: Given a string s, return all th ...
- [LeetCode] Palindrome Permutation I & II
Palindrome Permutation Given a string, determine if a permutation of the string could form a palindr ...
- [LeetCode] 266. Palindrome Permutation 回文全排列
Given a string, determine if a permutation of the string could form a palindrome. Example 1: Input: ...
- [LeetCode] 267. Palindrome Permutation II 回文全排列 II
Given a string s, return all the palindromic permutations (without duplicates) of it. Return an empt ...
- [LeetCode#267] Palindrome Permutation II
Problem: Given a string s, return all the palindromic permutations (without duplicates) of it. Retur ...
- leetcode 266.Palindrome Permutation 、267.Palindrome Permutation II
266.Palindrome Permutation https://www.cnblogs.com/grandyang/p/5223238.html 判断一个字符串的全排列能否形成一个回文串. 能组 ...
- [LeetCode] Next Permutation 下一个排列
Implement next permutation, which rearranges numbers into the lexicographically next greater permuta ...
随机推荐
- soapui中文操作手册(十)----REST Sample Project
第一步:打开MockService 1.双击MockService: 2.单击开始mockservice. 你会看到mockservice“端口8080上运行”. 参考: 配置使用MockServic ...
- ccc prefab
MonsterPrefab.js var Helpers = require('Helpers'); cc.Class({ extends: cc.Component, properties: { s ...
- BZOJ 3110 k大数查询 & 树套树
题意: 有n个位置,每个位置可以看做一个集合,现在要求你实现一个数据结构支持以下功能: 1:在a-b的集合中插入一个数 2:询问a-b集合中所有元素的第k大. SOL: 调得火大! 李建说数据结构题能 ...
- Leetcode Combination Sum II
Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in ...
- ACM 汉诺塔(三)
汉诺塔(三) 时间限制:3000 ms | 内存限制:65535 KB 难度:3 描述 在印度,有这么一个古老的传说:在世界中心贝拿勒斯(在印度北部)的圣庙里,一块黄铜板上插着三根宝石针.印度 ...
- BZOJ4556: [Tjoi2016&Heoi2016]字符串
Description 佳媛姐姐过生日的时候,她的小伙伴从某东上买了一个生日礼物.生日礼物放在一个神奇的箱子中.箱子外边写了 一个长为n的字符串s,和m个问题.佳媛姐姐必须正确回答这m个问题,才能打开 ...
- vim operation
note: 转自 www.quora.com ,很好的网站. 具体链接如下: https://www.quora.com/What-are-some-impressive-demos-of-Vim- ...
- iframe自适应高度js
<iframe src="http://www.fufuok.com/" id="iframepage" name="iframepage&qu ...
- HDU 5762
Teacher Bo Time Limit: 4000/2000 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others) Tot ...
- Ajax请求中的Redirect()
页面中有一个IsLogin()方法,用以判断该请求的触发者是否登录,如果登录了,则执行查询操作,如果没有登录,则Redirect()至登录界面 页面使用了较多的Ajax请求来获取数据,而在Ajax请求 ...