HDU 1575 Tr A

矩阵快速幂

#include<cstdio>

#include<cstring>

#include<cmath>

#include<algorithm>

using namespace std;



const int maxn=15;

const int MOD=9973;

int n,k;



struct Matrix

{

    int matrix[maxn][maxn];

    Matrix operator*(Matrix b);

};



Matrix Matrix::operator*(Matrix b)

{

    Matrix g;

    int i,j,k;

    for(i=1; i<=n; i++)

        for(j=1; j<=n; j++)

        {

            int sum=0;

            for(k=1; k<=n; k++)

                sum=(sum+(matrix[i][k]*b.matrix[k][j])%MOD)%MOD;

            g.matrix[i][j]=sum;

        }

    return g;

}



int main()

{

    int T;

    scanf("%d",&T);

    while(T--)

    {

        int i,j;

        scanf("%d%d",&n,&k);

        Matrix a;

        for(i=1; i<=n; i++)

            for(j=1; j<=n; j++)

                scanf("%d",&a.matrix[i][j]);

        Matrix c;

        for(i=1; i<=n; i++)

        {

            for(j=1; j<=n; j++)

            {

                if(i==j) c.matrix[i][j]=1;

                else c.matrix[i][j]=0;

            }

        }

        while(k!=0)

        {

            if(k%2==1) c=c*a,k--;

            else a=a*a,k=k/2;

        }

        int ans=0;

        for(i=1; i<=n; i++)

            ans=(ans+c.matrix[i][i])%MOD;

        printf("%d\n",ans);

    }

    return 0;

}