矩阵运算+快速幂+二分法 poj 3233

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

int n,m,k;

struct Matrix
{
    int data[31][31];
    
    void init()
    {
        memset(data,0,sizeof(data));
        for(int i=0;i<=30;i++)
            data[i][i] = 1;
    }
};

Matrix temp;

//矩阵乘法 
Matrix mul(Matrix a, Matrix b)
{
    Matrix res={{0}} ;
    for(int i = 0 ; i < n; i++)
    {
        for(int j = 0; j < n; j++)
        {
            res.data[i][j] = 0;
            for(int k= 0; k < n; k++)
            {
                res.data[i][j] = res.data[i][j] + (a.data[i][k] * b.data[k][j])%m;
                res.data[i][j] %= m;
            }
        }
    }
    return res;
}

//矩阵加法 
Matrix add(Matrix a, Matrix b)
{
    Matrix res;
    res.init();
    for(int i = 0 ; i < n; i++)
    {
        for(int j = 0; j < n; j++)
        {
            res.data[i][j] = a.data[i][j] + b.data[i][j];
            res.data[i][j] %= m;
        }
    }
    return res;
}


//矩阵快速幂 
Matrix power(Matrix a, int b)
{
    Matrix res;
    res.init();
    
    while(b!=0)
    {
        if(b%2==1)
        {
            res = mul(res,a);
        }
        b >>= 1;
        a = mul(a,a);
    }
    return res;
}

//二分法解决 
Matrix solve(int x)
{
    if(x==1)
        return temp;
    Matrix res,cur;
    if(x&1)
    {
        res = solve( x - 1);
        cur=power(temp,x);
        res=add(res,cur);
    }
    else{
        cur=power(temp,x/2);
        res = solve(x/2);
        res=add(res,mul(cur,res));
    }
    return res;
}

int main()
{
    scanf("%d %d %d",&n,&k,&m);
    //读取 
        for(int i = 0; i < n;i++)
        {
            for(int j = 0;j<n;j++)
            {
                scanf("%d",&temp.data[i][j]);
            }
        }
        
        Matrix s;
        
        s = solve(k);
        
        for(int i=0;i < n;i++)
        {
            for(int j=0;j < n-1;j++)
            {
                printf("%d ",s.data[i][j]);
            }
            printf("%d\n",s.data[i][n-1]);
        }
    
    return 0;
}