P1939 【模板】矩阵加速（数列）

Aimee

矩阵加速递推的模板了。

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#define int long long
#define ll long long
using namespace std;
const ll mod = 1e9+7;
ll n, a, b, m, p;
int t;
struct re {
    int rec[51][51];
} ans, tem, org;
re tim(re x, re y) {
	re tem;
    for (int i = 1; i <= 3; ++i) {
        for (int j = 1; j <= 3; ++j) {
            tem.rec[i][j] = 0;
            for (int k = 1; k <= 3; ++k) {
                tem.rec[i][j] += (x.rec[i][k] % mod) * (y.rec[k][j] % mod);
                tem.rec[i][j] %= mod;
            }
        }
    }
    return tem;
}
long long deal(){
	int x=n;
	if(x<=3){
		return 1;
	}
	tem=org;
	memset(ans.rec,0,sizeof(ans.rec));
	ans.rec[1][1]=ans.rec[2][2]=ans.rec[3][3]=1;
	while(x){
		if(x&1){
			ans=tim(ans,tem);	
		}
		x>>=1;
		 tem=tim(tem,tem);
	}
	return ans.rec[2][1]%mod;
}
signed main() {
	scanf("%d",&t);
	org.rec[1][1]=org.rec[1][3]=org.rec[2][1]=org.rec[3][2]=1;
	while(t--){
		scanf("%d",&n);
		cout<<deal()<<endl; 
	} 
    return 0;
}