345. 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".

Note:
The vowels does not include the letter "y".

翻转字符串中的所有元音

find_first_of

如果在一个字符串str1中查找另一个字符串str2，如果str1中含有str2中的任何字符，则就会查找成功，而find则不同

C++（9ms）：

class Solution {
public:
    string reverseVowels(string s) {
        int i = 0 ;
        int j = s.size() - 1 ;
        while(i < j){
            i = s.find_first_of("aeiouAEIOU",i) ;
            j = s.find_last_of("aeiouAEIOU",j) ;
            if (i < j){
                swap(s[i++],s[j--]) ;
            }
        }
        return s ;
    }
};