factorial trailing zeros test

test_trail0.py

# coding: utf-8
cache = dict()
def f(n):
    if n <= 0:
        return 0
    prev = cache.get(n-1)
    if not prev:
        s = 1;
        for i in range(1, n+1):
            s *= i
        cache[n] = s
    else:
        s = n * prev
    return s

def trail0(n):
    count = 0
    while n:
        r = n % 10
        if r:
            break
        count += 1
        n //= 10
    return count

l = lambda x:trail0(f(x))
print(trail0(f(30)))
print(l(40))