Omenat

#include <iostream>
#include <vector>

using namespace std;
using ll = long long;

int main() {
    int n;
    cin >> n;

    vector<int> ps;
    for (int i= 0; i <n;i++) {
        int p;
        cin >> p;
        ps.push_back(p);
    }

    ll sum = 0;
    for (int i=0;i<n;i++) {
        sum += ps[i];
    }

    if (sum % 3 == 0) {
        cout << n << "\n";
    } else if (sum % 3 == 1) {
        int has_mod1 = false;
        for (int i=0; i<n;i++) {
            if (ps[i]%3==1) {
                has_mod1=true;
            }
        }
        if (has_mod1) {
            cout << (n - 1) << "\n";
        } else {
            cout << (n - 2) << "\n";
        }
    } else {
        int has_mod2 = false;
        for (int i=0; i<n;i++) {
            if (ps[i]%3==2) {
                has_mod2=true;
            }
        }
        if (has_mod2) {
            cout << (n - 1) << "\n";
        } else {
            cout << (n - 2) << "\n";
        }
    }

    return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 1

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 2

Verdict: ACCEPTED

Test 12

Group: 2

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED

Test 16

Group: 3

Verdict: ACCEPTED

Test 17

Group: 3

Verdict: ACCEPTED

Test 18

Group: 3

Verdict: ACCEPTED