A 32-bit integer flip Python3

输入: 123
输出: 321

Example 2:

输入: -123
输出: -321

Example 3:

输入: 120
输出: 21

Suppose we have an environment can only store a 32-bit signed integer, then the value range is [- (2 ** 31), (2 ** 31) - 1]. Please According to this hypothesis, if integer overflow after reverse it returns 0.

code show as below:

class Solution:
    def reverse(self, x: int) -> int:
        int_max = 2**31-1
        int_min = -(2**31)
        rev = 0
        while x != 0:
            pop = -(abs(x)%10) if x < 0 else x%10       # 注意python3的取余方式（比如-123取余是7而不是-3）
            x = int(x/10)
            if rev > int(int_max/10) or rev == int(int_max/10) and pop > 7:     # int32最大值是2147483647，最后一位是7
                return 0
            if rev < int(int_min/10) or rev == int(int_min/10) and pop < -8:     # int32最小值是-2147483648，最后一位是8
                return 0
            rev = rev*10 + pop
        return rev