题解 | #阶乘末尾0的数量#

class Solution {
public:
    /**
     * the number of 0
     * @param n long长整型 the number
     * @return long长整型
     */
    long long thenumberof0(long long n) {
        // write code here
        long long res = 0;
        long long d = 5;
        // 看有多少个5的倍数
        while(d <= n) {
            res += n / d;
            d *= 5;
        }
        return res;
    }
};