7.Reverse Integer（16.45%）

题目：Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

理解：将输入的整数反向值输出，需要注意一点就是负号和反向之后值可能会超过int最大值的情况。

public class Solution {
    public int reverse(int x) {

        int result = 0;

        if (x < 0) {
            // x小于0
            char[] elementArray = String.valueOf(x).toCharArray();
            int len = elementArray.length;
            int biggestIndex = len - 1;
            char[] newArray = new char[len];
            newArray[0] = '-';
            for (int i = 1; i < len; i++) {
                newArray[len - i] = elementArray[i];
            }

            try {
                result = Integer.parseInt(new String(newArray));
            } catch (Exception e) {
                // TODO: handle exception
            }
        } else {
            // x大于等于0
            char[] elementArray = String.valueOf(x).toCharArray();
            int len = elementArray.length;
            int biggestIndex = len - 1;
            char[] newArray = new char[len];
            for (int i = 0; i < len; i++) {
                newArray[biggestIndex - i] = elementArray[i];
            }

            try {
                result = Integer.parseInt(new String(newArray));
            } catch (Exception e) {
                // TODO: handle exception
            }
        }

        return result;
    }
}