> #include <iostream.h> 
> #include <stdlib.h> 
> 
> int factorial(long int N, long int M) { 
>   long int i, j, result, dp; 
> 
>   dp=0; result = 1; 
> 
>   for(i = N-M+1; i <= N; i++) { 
>     j = i;                 
>     while (! (j % 2)) { j /= 2; dp++; } 
>     while (! (j % 5)) { j /= 5; dp--; } 
>     result = (result * (j % 10)) % 10; 
>   } 
> 
>   for(i = 1; i <= dp; i++) { result = (result * 2) %10; } 
> 
>   return result; 
> } 
> 
> void main() { 
>   long int N, M; 
> 
>   while (1){ 
>       cin >> N >> M; 
>       if(!cin) break; 
>       cout << factorial(N, M) << endl; 
>   } 
> } 

• Re:这样还超时，难道要用查表法... (85) zbleach 2008-09-08 15:28:27