点击打开链接 Problem Description WhereIsHeroFrom:             Zty, what are you doing ?
Zty:                                     I want to calculate N!......
WhereIsHeroFrom:             So easy! How big N is ?
Zty:                                    1 <=N <=1000000000000000000000000000000000000000000000…
WhereIsHeroFrom:             Oh! You must be crazy! Are you Fa Shao?
Zty:                                     No. I haven's finished my saying. I just said I want to calculate N! mod 2009


Hint : 0! = 1, N! = N*(N-1)!
 
Input Each line will contain one integer N(0 <= N<=10^9). Process to end of file.
 
Output For each case, output N! mod 2009
 
Sample Input 4 5  
Sample Output 24 120

#include #define LL long long const int mod = 2009; int main() { LL n; while(~scanf("%lld",&n)) { if(n >= mod) puts("0");//此处mod可以改为41，因为之前已经有个数可以整除 else { // 2009,7*7*41=2009; LL ans = 1; for(int i = n; i>1; i--) { ans = (ans*(i%mod))%mod;//ans=(ans%mod*i%mod)%mod; } printf("%lld ",ans); } } return 0; }