Factorial Trailing Zeroes

Problem page:https://leetcode.com/problems/factorial-trailing-zeroes

Solution

class Solution:
    def trailingZeroes(self, n: int) -> int:
        res = 0
        i = 5
        while n / i:
            count = n // i
            res += count
            i = i * 5
        return res

Complexity

• time: O(log n)
• space: O(1)