Leetcode•Jun 20, 2025
Factorial Trailing Zeroes
Hazrat Ali
Leetcode
Given an integer n, return the number of trailing zeroes in n!.
Note that n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1.
Example 1:
Input: n = 3 Output: 0 Explanation: 3! = 6, no trailing zero.
Example 2:
Input: n = 5 Output: 1 Explanation: 5! = 120, one trailing zero.
Example 3:
Input: n = 0 Output: 0
Solution
/**
* @param {number} n
* @return {number}
*/
const trailingZeroes = n => {
return n < 5 ? 0 : Math.floor(n / 5) + trailingZeroes(n / 5);
};