class Solution {
public:
    void reverseString(vector<char>& s) {
        int leftIndex = 0;
        int rightIndex = s.size() - 1;

        while (leftIndex < rightIndex) {
            // 交换字符
            char tmp = s[leftIndex];
            s[leftIndex] = s[rightIndex];
            s[rightIndex] = tmp;

            // 移动指针
            leftIndex++;
            rightIndex--;
        }
    }
};

class Solution {
public:
    void reverseString(std::vector<char>& s) {
        std::reverse(s.begin(), s.end());
    }
};