[leetcode] 345. Reverse Vowels of a String 解题报告

题目链接: https://leetcode.com/problems/reverse-vowels-of-a-string/

Write a function that takes a string as input and reverse only the vowels of a string.

Example 1:
Given s = "hello", return "holle".

Example 2:
Given s = "leetcode", return "leotcede".

思路: 用一个hash表存一下元音字符, 然后设置左右指针找到两个都是元音的位置交换一下就可以了. 注意字符是大小写都有的.

代码如下:

class Solution {public:    string reverseVowels(string s) {        if(s.length()==0) return "";        int left =0, right = s.length()-1;        set<char> hash{'a','e','i','o','u', 'A', 'E', 'I', 'O', 'U'};        while(left < right)        {            if(hash.count(s[left]) == 0)                left++;            if(hash.count(s[right]) == 0)                    right--;            if(hash.count(s[left])!=0 && hash.count(s[right])!=0)            {                swap(s[left], s[right]);                left++, right--;            }        }        return s;    }};