WA 5,6,9,10点

求大佬看看 算了半天所各个情况的统计可能，人已经麻了

#include<iostream>
#include<cmath>
#include<algorithm>
using namespace std;

int t, n, a, f[4], cnt;
long long ans;

int in() {
	int k = 0;
	char c = getchar();
	while (c < '0' || c>'9')
	{
		c = getchar();
	}
	while (c >= '0' && c <= '9') k = k * 10 + c - '0', c = getchar();
	return k;
}

void decompose(int a)
{
	f[3] += a / 3;
	if (a % 3 == 1)f[1]++;
	if (a % 3 == 2)f[2]++;
	
	return;
}

void solve()
{
	if (f[3] <= f[1])
	{
		ans = ans + f[1] + f[2];
		cout << ans << '\n';
		return;
	}
	else//f[1]少于f[3]，后面同理
	{
		ans += f[1];
		f[3] -= f[1];
	}

	if (f[3] <= f[2] * 2)
	{
		ans += f[3];
		ans += f[2] - f[3] / 2;
		cout << ans << '\n';
		return;
	}
	else
	{
		ans += f[2] * 2;
		f[3] -= f[2] * 2;

		long long z = (f[3] - 1) / 4;
		ans += 3 * z;

		z = (f[3] - 1) % 4;
		if (z == 0 || z == 1) ans += 2;
		else ans += 3;

		cout << ans << '\n';
		return;
	}
}

int main(){
	t = in();
	while (t--)
	{
		ans = 0;
		n = in();
		f[1] = 0;
		f[2] = 0;
		f[3] = 0;
		for (int i = 1;i <= n;i++)
		{
			a = in();
			decompose(a);
		}

		solve();
		
	}

	return 0;
}