172 - Factorial Trailing Zeroes

172. Factorial Trailing Zeroes

Problem Statement:

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

Constraints:

• 0 <= n <= 10⁴

Follow up: Could you write a solution that works in logarithmic time complexity?

Solution:

Java

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

...