LeetCode 344. Reverse String（字符串翻转）

原题网址：https://leetcode.com/problems/reverse-string/

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

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

方法：循环。

public class Solution {    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);    }}