문제
풀이
#include <iostream>
#include <vector>
using namespace std;
void solve(void) {
vector<long long> f(117);
f[1] = f[2] = f[3] = 1;
for (int i=4; i<=116; i++) f[i] = f[i-1] + f[i-3];
int n;
cin >> n;
cout << f[n];
}
int main(void) {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}