11727번: 2×n 타일링 2 ↗

#include <bits/stdc++.h>

#define for1(s,n) for(int i = s; i < n; i++)
#define for1j(s,n) for(int j = s; j < n; j++)
#define foreach(k) for(auto i : k)
#define foreachj(k) for(auto j : k)
#define pb(a) push_back(a)
#define sz(a) a.size()

using namespace std;
typedef unsigned long long ull;
typedef long long ll;
typedef vector <int> iv1;
typedef vector <vector<int> > iv2;
typedef vector <ll> llv1;
typedef unsigned int uint;
typedef vector <ull> ullv1;
typedef vector <vector <ull> > ullv2;

int N;
ll D[1100];

int f(int i) {
  if(D[i]) return D[i];

  if(i == 1) return D[i] = 1;
  if(i == 2) return D[i] = 3;


  return D[i] = (f(i - 1) + 2 * f(i - 2)) % 10007;
}

int main() {
  ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);

  cin >> N;

  cout << f(N);
}