/**
 * Created by gongmw on 2017-05-03.
 */
public class No344 {
    public String reverseString(String s) {
        if (s == null) return null;
        char[] sa = s.toCharArray();
        char[] r = new char[sa.length];
        for(int i=0; i<sa.length; i++) r[i] = sa[sa.length-1-i];
        return new String(r);
    }
}
