hdu_1005

 1 #include <cstdio>

 2 

 3 struct mat

 4 {

 5     int e[3][3];

 6     mat operator * (mat t){

 7         mat s;

 8         for (int i = 1; i <= 2; ++i){

 9             for (int j = 1; j <= 2; ++j){

10                 s.e[i][j] = 0;

11                 for (int k = 1; k <= 2; ++k){

12                     s.e[i][j] += e[i][k] * t.e[k][j] % 7; 

13                 }

14             }

15         }

16         return s;

17     }

18 };

19 int A,B,n;

20 

21 int main(int argc, char const *argv[])

22 {

23     while(scanf("%d%d%d",&A,&B,&n)&&(A||B||n)){

24         if(n == 1 || n == 2){

25             printf("1\n");

26             continue;

27         }

28         mat bas;

29         bas.e[1][1] = A; bas.e[1][2] = B;

30         bas.e[2][1] = 1; bas.e[2][2] = 0;

31         n-=3;

32         mat temp = bas;

33         while(n){

34             if(n&1){

35                 n--;

36                 bas = bas * temp;

37             }

38             temp = temp * temp;

39             n>>=1;

40         }

41         printf("%d\n", (bas.e[1][1] + bas.e[1][2]) % 7 );

42     }

43     return 0;

44 }