矩阵快速幂模板

struct Matrix {
    LL mat[MAXN][MAXN];
    int r,c;

    Matrix (int r = 0 ,int c = 0) { init(r,c); }

    void init(int r = 0,int c = 0) {
        this -> r = r;
        this -> c = c;
        memset(mat,0,sizeof(mat));
    }

    Matrix operator * (const Matrix &rhs) const {
        Matrix ret(r,rhs.c);
        for (int k = 0 ; k < c ; k++) {
            for (int i = 0 ; i < r ; i++) {
                if (mat[i][k] == 0) continue;
                for (int j = 0 ; j < rhs.c ; j++)
                    ret.mat[i][j] = (ret.mat[i][j] + mat[i][k] * rhs.mat[k][j]) % M;
            }
        }
        return ret;
    }
};

Matrix pow_mat(Matrix x,LL cnt) {
    Matrix ret(max(x.r,x.c),max(x.r,x.c));
    for (int i = 0 ; i < max(ret.r,ret.c) ; i++) ret.mat[i][i] = 1;
    while (cnt) {
        if (cnt & 1) ret = ret * x;
        x = x * x;
        cnt >>= 1;
    }
    return ret;
}