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

Example:
Given s = “hello”, return “olleh”.

这道题简单到爆了，给两个解，一个是我刚开始做题时候的，一个是一个月后的（是不是感觉提升很多）

类似题目：https://blog.jing.do/4772

public class Solution {
    public String reverseString(String s) {
        char[] sc = s.toCharArray();
        char[] res = new char[sc.length];
        int l=0;
        for(int i=sc.length-1; i>=0;i--){
            res[l] = sc[i];
            l++;
        }
        return new String(res);
    }
}

public class Solution {
    public String reverseString(String s) {
        char[] word = s.toCharArray();
        int i=0;
        int l=word.length -1;
        while(i<l){
            char temp = word[i];
            word[i] = word[l];
            word[l] = temp;
            i++;
            l--;
        }
        return new String(word);
    }
}