Leetcode 172. Factorial Trailing Zeroes

class Solution:
    def trailingZeroes(self, n):
        result = 1
        count = 0
        for i in range(1, n + 1):
            result *= i
        s = str(result)
        i = len(s) - 1
        while s[i] == '0':
            i -= 1
            count += 1
        return count

class Solution:
    def trailingZeroes(self, n):
        if n < 5:
            return 0
        result = 1
        count = 0
        exp = 16
        for i in range(5, n + 1, 5):
            result = result * i * exp
            while result % 10 == 0:
                count += 1
                result //= 10
        return count

class Solution:
    def trailingZeroes(self, n):
        count = 0
        for i in range(5, n + 1, 5):
            temp = i
            while temp % 5 == 0:
                count += 1
                temp //= 5
        return count

class Solution:
    def trailingZeroes(self, n):
        count = 0
        while n:
            n //= 5
            count += n
        return count