Card game

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

int n;
ll x[10101010];
ll f[10101010];

int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> x[i];
        if (i < 3) f[i] = 0;
        else {
            f[i] = max(x[i-1] + f[i-3], f[i-1]);
        }
    }
    cout << f[n];
}

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: UNKNOWN

Test 15

Verdict: UNKNOWN