Write a function that takes a string as input and returns the string reversed.

Example:

Given s = "hello", return "olleh".

链接：

3/8/2017

第4行的语法要注意

1 public class Solution {2     public String reverseString(String s) {3         if (s == null || s.length() < 2) return s;4         char[] c = new char[s.length()];5         for (int i = 0; i < s.length(); i++) c[i] = s.charAt(s.length() - i - 1);6         return new String(c);7     }8 }

别人有更好的方法可参考：