public int reverse(int x) {
        int sign = x < 0 ? -1 : 1;
        x = Math.abs(x);
        int num = 0;

        while (x > 0) {
            int d = x%10;
            if (num > Integer.MAX_VALUE/10 || (num == Integer.MAX_VALUE/10 && d > 7)) {
                return 0;
            }
            num = num*10 + d;
            x = x/10;
        }

        return sign*num;
    }