172. Factorial Trailing Zeroes

原题链接：https://leetcode.com/problems/factorial-trailing-zeroes/description/
这道题目虽然级别为easy，但是刚开始我并没有读懂题目，英文不好就是渣。。后来百度了下总算读明白题目了，然而还是不会做。最后还是百度了下看了下别人的答案：

/**
 * Created by clearbug on 2018/2/26.
 */
public class Solution {

    public static void main(String[] args) {
        Solution s = new Solution();
        System.out.println(s.trailingZeroes(1));
        System.out.println(s.trailingZeroes(2));
        System.out.println(s.trailingZeroes(3));
        System.out.println(s.trailingZeroes(4));
        System.out.println(s.trailingZeroes(5));
        System.out.println(s.trailingZeroes(6));
        System.out.println(s.trailingZeroes(7));
        System.out.println(s.trailingZeroes(8));
        System.out.println(s.trailingZeroes(9));
        System.out.println(s.trailingZeroes(10));
        System.out.println(s.trailingZeroes(11));
        System.out.println(s.trailingZeroes(12));
        System.out.println(s.trailingZeroes(13));
        System.out.println(s.trailingZeroes(14));
        System.out.println(s.trailingZeroes(15));
    }

    public int trailingZeroes(int n) {
        if (n < 1) {
            return 0;
        }
        int res = 0;
        while (n >= 5) {
            res += n / 5;
            n = n / 5;
        }
        return res;
    }
}