Reverse Integer

Given a 32-bit signed integer, reverse digits of an integer.

Example 1:

Input: 123
Output: 321
Example 2:

Input: -123
Output: -321
Example 3:

Input: 120
Output: 21
Note:
Assume we are dealing with an environment which could only hold integers within the 32-bit signed integer range. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

class Solution:
    def reverse(self, x):
        """
        :type x: int
        :rtype: int
        """
        s = str(x)
        if s[0] == "-":
            r = "-" + s[1:][::-1]
        else:
            r = s[::-1]
        r = int(r)
        if r > 2**31 or r < -(2**31):
            r = 0
        return r