Torni

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

ll a[1111000], b[1111000], c[1111000], M=1e9+7;

void tapaus(){
    int n;
    cin >> n;
    cout << a[n] << "\n";
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    a[0]=1;
    b[0]=1;
    a[1]=2;
    b[1]=1;
    c[1]=1;
    for (int i=2; i<=1000000; ++i){
        b[i]=(b[i-1]+a[i-1])%M;
        c[i]=(4*c[i-1]+b[i-1])%M;
        a[i]=(c[i]+b[i])%M;
    }
    int t;
    cin >> t;
    while (t--) tapaus();
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 2, 3

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED