HDU 3123-GCC(递推)

Posted 2020-06-14

GCC

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)
Total Submission(s): 3993    Accepted Submission(s): 1304

Problem Description

The GNU Compiler Collection (usually shortened to GCC) is a compiler system produced by the GNU Project supporting various programming languages. But it doesn’t contains the math operator “!”.
In mathematics the symbol represents the factorial operation. The expression n! means "the product of the integers from 1 to n". For example, 4! (read four factorial) is 4 × 3 × 2 × 1 = 24. (0! is defined as 1, which is a neutral element in multiplication, not multiplied by anything.)
We want you to help us with this formation: (0! + 1! + 2! + 3! + 4! + ... + n!)%m

 

Input

The first line consists of an integer T, indicating the number of test cases.
Each test on a single consists of two integer n and m.

 

Output

Output the answer of (0! + 1! + 2! + 3! + 4! + ... + n!)%m.

Constrains
0 < T <= 20
0 <= n < 10^100 (without leading zero)
0 < m < 1000000

 

Sample Input

1
10 861017

 

Sample Output

593846
求 n!%m=(n-1)!*n%m; 即f(n)=f(n-1)*n%m;
并且  (0!+1!+...n!)%m 假设n>m 那么以后的k!都能够被m整除。。忽略
然后 。。递推就能够了
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cctype>
#include <cmath>
#include <cstdlib>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <list>
#define ll long long
using namespace std;
const int INF=1<<27;
const int maxn=1010;
int main()
{
	int t;
	char n[200];int m;
	scanf("%d",&t);
	while(t--)
	{
		scanf("%s %d",n,&m);
		int tem;
		if(strlen(n)>=7)
		tem=999999;
		else
		sscanf(n,"%d",&tem);
		tem=min(m,tem);
		ll f1=1%m,fn,ans=f1;
		for(int i=1;i<=tem;i++)
		{
			fn=f1*i%m;
			ans+=fn;
			f1=fn;
		}
		printf("%lld\n",ans%m);
	}
    return 0;
}