python3 实现数学黑洞6174

# -*- coding: utf-8 -*-
from functools import reduce
x = str(input("请输入四位数或者三位数的数字： "))
times = 1
while True:
    if len(x) > 4:
        print("不能超过4位数")
        break 
    max_math = sorted(x,reverse=True)
    min_math = sorted(x)
    max_math_switch_str = int(reduce(lambda x,y:x+y,max_math))
    min_math_switch_str = int(reduce(lambda x,y:x+y,min_math))
    s = max_math_switch_str-min_math_switch_str
    print("now",times,max_math_switch_str,"-",min_math_switch_str,"=",s)
    if s == 6174:
        break
    if s == 495:
        break
    x = str(s)
    times += 1