Card game

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <cmath>

using namespace std;

using ll  = long long;
using vi  = vector<int>;
using vc = vector<char>;
using vll = vector<long long>;
using vs  = vector<string>;
using vb = vector<bool>;
using vvi  = vector<vector<int>>;
using vvll = vector<vector<long long>>;
using vvc  = vector<vector<char>>;
using vvb  = vector<vector<bool>>;
using pii = pair<int, int>;


#define all(x) (x).begin(), (x).end()
#define pb push_back
#define sz(x) ((int)(x).size())
#define forn(i, n) for (int i = 0; i < (n); ++i)

using namespace std;
int n;


int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  
  cin >> n;

  vll x(n+1);

  for(int i = 1; i <= n; i++) cin >> x[i];

  vll dp(n+1, 0);

  for(int i = 3; i <= n; i++){
    dp[i] = max(dp[i-1], dp[i-3]+x[i-1]);
  }

  cout << dp[n] << endl;

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED