LeetCode之Reverse String

1、題目：

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

Example:

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

2、代碼實作：

代碼實作1:

public static String reverseString(String s) {
        if (s == null) {
            return null;
        }
        if (s.length() == 0) {
            return "";
        }
        int length = s.length();
        char[] chars = s.toCharArray();
        String result = "";
        for (int i = chars.length - 1; i >=0; --i) {
            result += chars[i];
        }
        return result;
    }      

代碼實作2:

public String reverseString(String s) {
        return new StringBuffer(s).reverse().toString();
    }