2. 尾部的零

设计一个算法，计算出n阶乘中尾部零的个数

public class Solution {
    /*
     * @param n: An integer
     * @return: An integer, denote the number of trailing zeros in n!
     */
    public long trailingZeros(long n) {
        // write your code here, try to do it without arithmetic operators.
        long sum = 0;
        while(n>0){
            sum += n / 5;
            n /= 5;
        }
        return sum;
    }
}