Omenat

input/code.cpp: In function 'long int etsi(long int, std::vector<long int>&, long int)':
input/code.cpp:10:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (long i = a; i < p.size(); i++) {
                     ^

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

long etsi(long s, vector<long> &p, long a) {
	long m = 0;

	for (long i = a; i < p.size(); i++) {
		if ((s + p[i]) % 3 == 0) {
			m = max(m, 1l);
		}

		long tulos = etsi(s + p[i], p, i + 1);

		if (tulos) {
			m = max(m, 1l + tulos);
		}
	}

	return m;
}

int main() {
    cin.sync_with_stdio(false);
    cin.tie(0);

    long n;
    cin >> n;
    vector<long> p;
    long k = 0;

    for (long i = 0; i < n; i++) {
    	long o;
    	cin >> o;

    	if (o % 3 == 0) {
    		k++;
    	} else {
    		p.push_back(o);
    	}
    }

    k += etsi(0, p, 0);

    cout << k << "\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: TIME LIMIT EXCEEDED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 11

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 14

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 15

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 16

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 17

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 18

Group: 3

Verdict: TIME LIMIT EXCEEDED