P1939 【模板】矩阵加速(数列)
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;
}