广义斐波那契数列 矩阵乘法

 

Code:

#include<cstdio>         
#include<algorithm>
using namespace std;
long long n,p,q,a1,a2,mod;
struct matrix{
	long long c[2][2];
};
matrix I={1,0,0,1};              
matrix A={0,0,0,0};
matrix R={0,1,0,0};
matrix operator*(matrix a,matrix b){
	matrix C=A;
	for(int i=0;i<2;++i)                             
	     for(int j=0;j<2;++j)               
		   for(int k=0;k<2;++k)
		        C.c[i][j]=(C.c[i][j]+(a.c[i][k]*b.c[k][j])%mod)%mod;
	return C;				
}
matrix pow(matrix a,long long k){
	matrix ans=I;
	while(k){
		if(k&1)ans=ans*a;
		a=a*a;k/=2;
	}
	return ans;
}
int main(){
	scanf("%lld %lld %lld %lld %lld %lld",&p,&q,&a1,&a2,&n,&mod);
	if(n==1){printf("%lld",a1%mod);return 0;}
	if(n==2){printf("%lld",a2%mod);return 0;}
	matrix fin=A;
	fin.c[0][0]=a2;
	fin.c[0][1]=a1;
	matrix M=R;
	M.c[0][0]=p;
	M.c[1][0]=q;
	matrix ans=fin*pow(M,n-2);
	printf("%lld",ans.c[0][0]);
	return 0;
}