递归和信用卡的Luhn算法

这里用python做一个mutual recursion

 

def split(n):
    return n//10, n%10

def luhn_sum(n):
    if n<10:
        return n
    else:
        rest, last = split(n)
        return luhn_double_sum(rest) + last

def luhn_double_sum(n):
    rest, last = split(n)
    luhn_digit = split(2*last)[0] + split(2*last)[1]
    if n<10:
        return luhn_digit
    else:
        rest, last = split(n)
        return luhn_sum(rest) + luhn_digit

 

见过的PL们 Python Recursion Luhn Algorithm Comments(3) 2015年6月30日 22:15