7. Reverse Integer

7. Reverse Integer

class Solution(object):
    def reverse(self, x):
        """
        :type x: int
        :rtype: int
        """
        if x < 0:
            return -self.reverse(-x)
        res = 0
        while x:
            res = res * 10 + x % 10
            x = x // 10
            if res > 2**31 - 1:
                return 0
        return res