@[引领天下](/space/show?uid=39863) 卡常加两个难度（逃
by chen_zhe @ 2018-08-07 21:25:56
@[chen_zhe](/space/show?uid=8457) 什么鬼……这题目哪里卡常了？？？
by 引领天下 @ 2018-08-07 21:28:44
@[chen_zhe](/space/show?uid=8457) 这个大佬0ms[AC](https://www.luogu.org/record/show?rid=9427627)
by 引领天下 @ 2018-08-07 21:29:54
@[引领天下](/space/show?uid=39863) 正常做法直接模拟容易被卡常啊QAQ我被卡过几次
by chen_zhe @ 2018-08-07 21:36:33
@[引领天下](/space/show?uid=39863) 双循环60分，单循环才能100分，但难想到，~~本蒟蒻被卡了3次~~
by skiy_gyx @ 2018-08-08 11:43:03
纯数论题
by Ricken @ 2019-08-30 10:45:19
```cpp
#include<bits/stdc++.h>
using namespace std;
long long n,ans;
int main() {
ios::sync_with_stdio(false);
cin >> n;
for(register int i = 5; i <= n - 5; i += 5) {
int t = 0,j = i;
while(j) {
j /= 5;
t += j;
}
ans += t * 5;
}
int t = 0,j = n;
while(j) {
j /= 5;
t += j;
}
cout << ans + (n - n / 5 * 5 + 1) * t;
return 0;
}
```
by WDySrDbMoAuMc @ 2019-09-23 22:05:28