/*
 * @Description:
 * @Version: 1.0
 * @Autor: zhuyijun
 * @Date: 2021-12-28 17:12:21
 * @LastEditTime: 2022-01-21 15:35:19
 */
#include <bits/stdc++.h>
using namespace std;
void reverseString(vector<char>& s) {
  if (s.size() < 2) {
    return;
  }
  int l = 0, r = s.size() - 1;
  while (l < r) {
    char temp = s[r];
    s[r] = s[l];
    s[l] = temp;
    l++, r--;
  }
}