345. 反转字符串中的元音字母 2021-08-19

class Solution {
private:
    set<char> vowels = {'a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U'};
public:
    string reverseVowels(string s) {
        int p1 = 0, p2 = s.length() - 1;
        while (p1 < p2) {
            while (p1 < p2 && vowels.count(s[p1]) == 0) {
                ++p1;
            }
            while (p1 < p2 && vowels.count(s[p2]) == 0) {
                --p2;
            }
            if (p1 < p2)
                swap(s[p1], s[p2]);
            ++p1;
            --p2;
        }
        return s;
    }
};