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 store integers within the 32-bit signed integer range: [−2 ^ 31 ,2 ^ 31 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

Python代码:

class Solution:
    def reverse(self, x):
        """
        :type x: int
        :rtype: int
        """
        str_x = str(abs(x))
        result = int(str_x[::-1])
        if x < 0 :
            result *= -1

        if (result > 2**31 or result < -(2**31-1)) :
            return 0

        return result

思路:

取绝对值 , 转化为字符串 , 逆序 , 再转化为数字 , 判断是否溢出