LeetCode 344. Reverse String

public class Solution {    public String reverseString(String s) {        char tmp[] = s.toCharArray();int l = tmp.length;for(int i = 0; i < l / 2; i++) {char t = tmp[l - i - 1];tmp[l - i - 1] = tmp[i];tmp[i] = t;}return String.valueOf(tmp);    }}