1、http://acm.sdut.edu.cn/sdutoj/showproblem.php?pid=1919&cid=1199
2、GCC
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.
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 the answer of (0! + 1! + 2! + 3! + 4! + ... + n!)%m.
1 10 861017
593846
3、超时代码:
#include<stdio.h> #include<string.h> int dp[1000005]; int jie(int n) { int ans=1; if(dp[n]!=0) return dp[n]; for(int i=n;i>=1;i--) { if(dp[i]!=0) { ans*=dp[i]; break; } else ans*=i; } return ans; } int main() { int t,n,m; scanf("%d",&t); memset(dp,0,sizeof(dp)); for(int i=0;i<t;i++) { long long sum=0; scanf("%d%d",&n,&m); if(n>m) n=m-1; for(int j=0;j<=n;j++) { dp[j]=jie(j); sum+=dp[j]%m; } printf("%lld\n",sum%m); } return 0; }