hdu 3123

GCC

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)
Total Submission(s): 3754    Accepted Submission(s):
1216

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

 

Source

2009
Asia Wuhan Regional Contest Online

 

数字看起来非常巨大，吓人。

但是如果n!%p =0  那么 (n+1)!%p =0;

就这样。

 #include<iostream>
 #include<stdio.h>
 #include<cstring>
 #include<cstdlib>
 using namespace std;
 typedef __int64 LL;

 void solve(int sum,int p)
 {
     int i;
     LL ans =  ,cur =  % p ;
     for(i=;i<=sum;i++)
     {
         ans = (ans * i)%p;
         cur = (cur + ans)%p;
         if(ans == )break;
     }
     printf("%I64d\n",cur);
 }
 int main()
 {
     int T;
     int i,p;
     char a[];
     scanf("%d",&T);
     while(T--)
     {
         scanf("%s%d",a,&p);
         if(p==)
         {
             printf("0\n");
             continue;
         }
         int sum = ;
         for(i=;a[i]!='\0';i++)
         {
             sum=sum*+a[i]-'';
             if(sum>=p)break;
         }
         solve(sum,p);
     }
     return ;
 }