Factorial Zeros
def convert_to_closest_value_divisible_by_5(num):
"""
:param num: input
:return: either ?5 or ?0 for two-digit number
"""
last_digit = int(num % 10)
base = num - last_digit
if last_digit >= 5:
base += 5
return base
def find_factorial_zeros(num):
count = 0
base = convert_to_closest_value_divisible_by_5(num)
if num == 0:
return 1
while base > 0:
current = base
# while it is divisible by 5, increase count by 1
while current % 5 == 0 and current > 0:
count += 1
current /= 5
base -= 5
return count
if __name__ == '__main__':
assert convert_to_closest_value_divisible_by_5(18) == 15
assert convert_to_closest_value_divisible_by_5(20) == 20
assert convert_to_closest_value_divisible_by_5(13) == 10
assert convert_to_closest_value_divisible_by_5(10) == 10
assert find_factorial_zeros(20) == 4
assert find_factorial_zeros(19) == 3
assert find_factorial_zeros(10) == 2
assert find_factorial_zeros(5) == 1
assert find_factorial_zeros(0) == 1
assert find_factorial_zeros(1) == 0
Updated on 2020-05-26