sdut——GCC

题目描述

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. 

输入

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. 

0 < T <= 20
0 <= n < 10¹⁰⁰ (without leading zero) 
0 < m < 1000000 

输出

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

示例输入

1 10 861017 

示例输出

593846

当n>m的时候，n%m==0,所以只要加到m-1个数的阶乘即可

#include <iostream>#include <stdio.h>#include <cstring>#include <algorithm>using namespace std;char s[107];int main(){int t;cin>>t;while(t--){long long  m; scanf("%s%lld",&s,&m);long long sum=1;long long number=0;long long count=1;        int len=strlen(s);    if(len>7)    {    number=m-1;    }    else    {    for(int i=0;i<len;i++)    {    number=number*10+(s[i]-'0');    }    }    if(number>=m)    number=m-1;    for(int i=1;i<=number;i++)    {    count=(i*count)%m;    sum=(sum+count)%m;       }    cout<<sum%m<<endl;}return 0;}