package leetcode.string; public class ReverseString { public void reverseString(char[] s) { reverse(s, 0); } private void reverse(char[] s, int pos) { if (pos == s.length/2) return; char tmp = s[pos]; s[pos] = s[s.length - pos - 1]; s[s.length - pos - 1] = tmp; reverse(s, pos + 1); } }