Luogu P1962 斐波那契数列

Code

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<queue>
using namespace std;
typedef long long ll;
ll n;
const int mod = 1000000007;
struct Matrix{
    int r,c;
    ll data[10][10];
    Matrix(){
        memset(data,0,sizeof(data));
    }
    Matrix(int r,int c){
        this->r = r;
        this->c = c;
        memset(data,0,sizeof(data));
    }
    ll* operator [] (int pos){
        return data[pos];
    }
    Matrix operator * (Matrix B){
        Matrix C(r,B.c);
        for(int i = 1;i <= r;i++){
            for(int j = 1;j <= B.c;j++){
                for(int k = 1;k <= c;k++){
                    C[i][j] = (C[i][j]%mod + (data[i][k]%mod)*(B[k][j]%mod)%mod)%mod;
                }
            }
        }
        return C;
    }
};
Matrix Pow(Matrix A,ll b){
    Matrix ret(A.r,A.c);
    for(int i = 1;i <= A.r;i++) ret[i][i] = 1;//unit matrix   <==>  1  (integer)
    while(b){
        if(b&1) ret = ret*A;
        A = A*A;
        b >>= 1;
    }
    return ret;
}
void solve(){
    if(n <= 2){
        printf("1
");
        return;
    }
    Matrix P(2,2);
    P[1][1] = P[1][2] = P[2][1] = 1;
    P[2][2] = 0;
    P = Pow(P,n - 2);
    printf("%lld
",(P[1][1]%mod + P[1][2]%mod)%mod);
    return;
}
int main(){
    scanf("%lld",&n);
    solve();	
    return 0;
}