[Leetcode] Reverse Integer

Reverse digits of an integer.

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

Have you thought about this? Here are some good questions to ask before coding. Bonus points for you if you have already thought through this!
If the integer's last digit is 0, what should the output be? ie, cases such as 10, 100.
Did you notice that the reversed integer might overflow? Assume the input is a 32-bit integer, then the reverse of 1000000003 overflows. How should you handle such cases?
For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
Update (2014-11-10):
Test cases had been added to test the overflow behavior.

Pay attention to the case of overflow and the case when x = Integer.MIN_VALUE. In this case, you could not directly let x = -x, since it would overflow again, but we know for sure that the reverse of it would overflow so we could directly return 0.

    public int reverse(int x) {
        boolean sign = true;
        if(x < 0) {
            sign = false;
            if(x == Integer.MIN_VALUE) // overflow
                return 0;
            x = -x;
        }
        int res = 0;
        while(x != 0) {
            int digit = x % 10;
            if((Integer.MAX_VALUE - digit) / 10 < res) { // overflow
                return 0;
            }
            res = res * 10 + digit;
            x = x / 10;
        }
        if(sign == false)
            return -res;
        return res;
    }