luogu P1939 【模板】矩阵加速（数列）

二次联通门 : luogu P1939 【模板】矩阵加速（数列）

/*
    luogu P1939 【模板】矩阵加速（数列）

    模板题不说什么
　　 许久不写代码。。
    感觉好别扭

     
*/
#include <cstring>
#include <cstdio>

#define Mod 1000000007

void read (long long &now)
{
    now = 0;
    register char word = getchar ();

    while (word < '0' || word > '9')
        word = getchar ();
    while (word >= '0' && word <= '9')
    {
        now = now * 10 + word - '0';
        word = getchar ();
    }
}

struct Martix
{
    static const int _L = 3;
    long long data[_L][_L];
    
    Martix operator * (const Martix &now) const
    {
        Martix res;
        for (register int i = 0, j, k; i < _L; i ++)
            for (j = 0; j < _L; j ++)
            {
                res.data[i][j] = 0;
                for (k = 0; k < _L; k ++)
                    res.data[i][j] = (res.data[i][j] + this->data[i][k] * now.data[k][j]) % Mod;
            }
        
        return res;
    }
    
    void Fill ()
    {
        for (register int i = 0, j; i < _L; i ++)
            for (j = 0; j < _L; j ++)
                this->data[i][j] = 0;
                
        this->data[0][2] = 1;
        this->data[1][0] = 1;
        this->data[2][1] = 1;
        this->data[2][2] = 1;
    }
};

Martix operator ^ (Martix now, long long P)
{
    Martix Answer;
    
    memset (Answer.data, 0, sizeof Answer.data);
    
    Answer.data[0][0] = 1;
    Answer.data[1][1] = 1;
    Answer.data[2][2] = 1;
    
    for (; P; P >>= 1)
    {
        if (P & 1)
            Answer = Answer * now;
        
        now = now * now;
    }
    
    return Answer;
}

long long N;

int main (int argc, char *argv[])
{
    long long T;
    Martix A;
    
    for (read (T); T --; )
    {
        read (N);
        if (N <= 3 && N > 0) 
        {
            putchar ('1');
            putchar ('
');
            continue;
        } 
        else if (N <= 0) 
        {
            putchar ('0'); 
            putchar ('
');
            continue;
        }
         
        N -= 3;
        
        A.Fill ();
        
        A = A ^ N;
        printf ("%lld
", (A.data[2][0] + A.data[2][1] + A.data[2][2]) % Mod);
    }
    return 0;
}