JonnyF--Reverse Integer

Reverse digits of an integer.

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

解题思路：

      题目的意思是要将一个整数反转， 当反转后的数 溢出时返回0。注意：这里要注意的是反转后是否会越界。

class Solution:
    # @return an integer
    def reverse(self, x):
        if x >= 0:
            leave = x
            sign = 1
        else:
            leave = -x
            sign = -1

        result = 0
        while 0 != leave:
            result = result * 10 + leave % 10
            leave /= 10
        if result > 2**31:
            return 0
        else:
            return result * sign