7. Reverse Integer-python

Reverse digits of an integer.

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

Note: The input is assumed to be a 32-bit signed integer. Your function should return 0 when the reversed integer overflows.

Code

class Solution(object):
    def reverse(self, x):
        """
        :type x: int
        :rtype: int
        """
        isNegative = x < 0
        if isNegative:
            x=-x
        rtn = 0;
        max32 = 2**31-1  # 32位符号整数的最大值
        while x != 0:
            postBit = x%10
            iterval = rtn*10 + postBit
            if iterval > max32:
                return 0
            rtn = iterval
            x /= 10
        return -rtn if isNegative else rtn