hdu 2855 Fibonacci Check-up (矩阵)

题目链接：hdu 2855 Fibonacci Check-up

题意&题解：

#include<bits/stdc++.h>
#define mst(a,b) memset(a,b,sizeof(a))
#define F(i,a,b) for(int i=a;i<=b;i++)
using namespace std;
typedef long long ll;

const int mat_N=2;
int mo;
struct mat{
    int c[mat_N][mat_N];
    void init(){mst(c,0);}
    mat operator*(mat b){
        mat M;int N=mat_N-1;M.init();
        F(i,0,N)F(j,0,N)if(c[i][j])F(k,0,N)M.c[i][k]=(M.c[i][k]+c[i][j]*b.c[j][k])%mo;
        return M;
    }
    mat operator^(ll k){
        mat ans,M=(*this);int N=mat_N-1;ans.init();
        F(i,0,N)ans.c[i][i]=1;
        while(k){if(k&1)ans=ans*M;k>>=1,M=M*M;}
        return ans;
    }
}A,B;

int main()
{
    A=(mat){1,1,1,0};
    int t,k;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&k,&mo);
        if(k==0){puts("0");continue;}
        B=A^(2*k-1);
        printf("%d
",B.c[0][0]);
    }
    return 0;
}