LeetCode_One question per day_python_Question 7 integer flip

Given a 32-bit signed integer, you need to invert the digits on each of the integers.

Example 1:

Input: 123
Output: 321
 Example 2:

Input: -123
Output: -321
Example 3:

Input: 120
Output: 21
Note:

Assuming that our environment can only store 32-bit signed integers, the value range is [−231, 231 − 1]. According to this assumption, if the integer overflows after the inversion, it returns 0.

Source: LeetCode
 

class Solution:
    def reverse(self, x: int) -> int:
        #   先取 绝对值 再转化为字符串
        s = str(abs(x))
        #   取反
        s = s[::-1]
        if x < 0:
           s = '-' + s
        #   转化为整型
        res = int(s)
        if -2 ** 31 <= res <= 2 **31 - 1:
            return res
        else:
            return 0