[leetcode]: 345. Reverse Vowels of a String

1.题目

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”.
给一个字符串，翻转其中的元音字母

2.分析

两个指针分别从头部和尾部开始往中间遍历。遇到元音字母则swap。

3.代码

class Solution {public:    bool isVowel(char c) {        return c == 'A' || c == 'a' || c == 'E' || c == 'e' || c == 'I' || c == 'i' || c == 'O' || c == 'o' || c == 'U' || c == 'u';    }    string reverseVowels(string s) {        int i = 0;        int j = s.size() - 1;        while (i < j) {            if (isVowel(s[i]) && isVowel(s[j])) {                swap(s[i], s[j]);                ++i;                --j;            }            else if (!isVowel(s[i]))                ++i;            else if (!isVowel(s[j]))                --j;        }        return s;    }};