Problem #172: Factorial Trailing Zeroes

Intuition & Strategy Breakdown

Count total factors of 5 in factorial numbers by summing n // 5 + n // 25 + n // 125...

Python Solution

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

Java Solution

class Solution {
    public int trailingZeroes(int n) {
        int count = 0;
        while (n > 0) {
            n /= 5;
            count += n;
        }
        return count;
    }