172\. Factorial Trailing Zeroes

Medium

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:**

*   <code>0 <= n <= 10<sup>4</sup></code>

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