
https://leetcode.com/problems/reverse-string/description/
class Solution {
public void reverseString(char[] s) {
int start = 0;
int end = s.length - 1;
while (start < end) {
char tmp = s[start];
s[start] = s[end];
s[end] = tmp;
start ++;
end --;
}
}
}
