dlnumk的博客

Problem Description Tina Town is a friendly place. People there care about each other. Tina has a ball called zball. Zball is magic. It grows larger every day. On the first day, it becomes 1 ti

首先我们要知道0是怎么来的 两个个位数相乘只有2*5=10会出现一个0 所以我们只要找出因子2和5能匹配多少对 因为在N的阶乘中因子为2的个数远远大于因子为5的个数 比如5！=120 是因为2*5 = 10能匹配出一对来而4还可以分成2*2所以2的数目远远大于5 所以下一步只要找出因子是5的个数 long long n; cin>>n; long long ans