2^x mod n = 1

HUD 1395 / ZOJ 1489

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 int main(int argc, char *argv[])
 6 {
 7     int n,flag;
 8     long s;
 9     
10     while(cin>>n){    
11         flag =0;
12         s=1;            
13           for(int x=1;x<n+1;x++){
14             s *= 2;
15             s %= n;
16             if(s == 1){
17                 flag = x;
18                 break;                    
19             }
20         }
21         if(flag!=0)
22             cout<<"2^"<<flag<<" mod "<<n<<" = 1"<<endl;
23         else
24             cout<<"2^?"<<" mod "<<n<<" = 1"<<endl;
25     }
26 
27     return 0;
28 }

 

posted @ 2014-07-27 10:50  算法研究  阅读(140)  评论(0)  编辑  收藏  举报