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
",ans);
    }
    return 0;
}