1
class Solution {
2
  public void reverseString(char[] s) {
3
    int start = 0, end = s.length - 1;
4

5
    while (start < end) {
6
      char temp = s[end];
7
      s[end] = s[start];
8
      s[start] = temp;
9
      start++;
10
      end--;
11
    }
12
  }
13
}