LeetCode-7

class Solution:
    def reverse(self, x: int) -> int:
        num = 0
        #返回x的绝对值给a
        a = abs(x)
        while(a != 0):
            #123
            #a=123
            #num=0
            #1、
            #a=a/10
            #num=a%10
            num = num*10+(a%10)
            a = int(a/10)
            
        if x<0 and num<2147483647:
            return -num
        elif x>0 and num<=2147483647:
            return num
        else:
            return 0