Omenat

#include <iostream>
#include <string>
#include <math.h>
#include <map>
#include <algorithm>
#include <vector>
#include <fstream>
#include <set>
#include <unordered_map>
#include <queue>
#include <climits>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define LOOP(i,a,l) for (int i = a; i < l; i++)
#define LUO_VERKKO LOOP(i,0,m) {int a,b; cin >> a >> b; v[a].push_back(b); v[b].push_back(a);}
#define COLLECT for (int i = 0; i < n; i++) cin >> s[i]
#define A 999999999999999999LL
//https://cses.fi/dt/
int n, m, q;
int d[101010][3];
int s[101010];
int main() {
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> s[i]; s[i] %= 3;
	}
	sort(s,s + n);
	auto vi = lower_bound(s, s + n,2);
	auto vi2 = lower_bound(s, s + n, 1);
	int kakkosia = (s+n) - vi;
	int ykkosia = vi - vi2;
	int ym = 0;
	if (ykkosia % 3 != 0) {
		if (ykkosia + 2 % 3 == 0 && kakkosia) {
			kakkosia--;
		}
		else {
			ym = ykkosia % 3;
			ykkosia -= (ykkosia % 3);
		}
	}
	if (kakkosia % 3 != 0) {
		if (ym < kakkosia % 3) {
			if (kakkosia % 3 == 2) {
				kakkosia--;
			}
		}
		else ykkosia += kakkosia % 3;
	}
	cout << (vi2 - s) + ykkosia + kakkosia;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: WRONG ANSWER

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: WRONG ANSWER

Test 9

Group: 2

Verdict: WRONG ANSWER

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: WRONG ANSWER

Test 15

Group: 3

Verdict: WRONG ANSWER

Test 16

Group: 3

Verdict: ACCEPTED

Test 17

Group: 3

Verdict: ACCEPTED

Test 18

Group: 3

Verdict: ACCEPTED