2748번: 피보나치 수 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[110];

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

  cin >> N;

  D[0] = 0;
  D[1] = 1;

  for(int i = 2; i <= N; i++) {
    D[i] = D[i-1]+ D[i-2];
  }

  cout << D[N];
}