Submission #705362

#	Time	Username	Problem	Language	Result	Execution time	Memory
705362		Chal1shkan	Logičari (COCI21_logicari)	C++14	20 / 110	239 ms	26920 KiB

Main

# include <bits/stdc++.h>
 
# define pb push_back
# define ff first
# define ss second
# define nl "\n"
# define sz(x) ((int)(x).size())
# define deb(x) cerr << #x  << " = " << x << endl; 
# define pll pair <ll, ll>
 
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
 
const ll maxn = 1e6 + 25;
const ll inf = 1e18 + 0;
const ll mod = 1e9 + 123;
const ll dx[] = {-1, 1, 0, 0};
const ll dy[] = {0, 0, -1, 1};
 
using namespace std;

ll n, col[maxn];
vector <ll> g[maxn];
bool used[maxn];
bool bad;

void ok (ll v)
{
	used[v] = 1;
	ll cnt = 0;
	for (ll to : g[v])
	{
		cnt += (col[to] == 1);
	}
	if (cnt != 1)
	{
		bad = 1;
	}
	for (ll to : g[v])
	{
		if (!used[to])
		{
			ok(to);
		}
	}
}

void ma1n (/* SABR */)
{
	cin >> n;
	for (ll i = 1, u, v; i <= n; ++i)
	{
		cin >> u >> v;
		g[u].pb(v);
		g[v].pb(u);
	}
	if (n <= 20)
	{
		ll ans = n + 1;
		for (ll mask = 0; mask < (1LL << n); ++mask)
		{
			bad = 0;
			ll cnt = 0;
			for (ll i = 0; i < n; ++i)
			{
				used[i + 1] = 0;
				col[i + 1] = 0;
				if (mask & (1LL << i))
				{
					cnt++;
					col[i + 1] = 1;
				}
			}
			ok(1);
			if (!bad)
			{
				ans = min(ans, cnt);
			}
		}
		if (ans == n + 1) ans = -1;
		cout << ans;
	}
	else
	{
		bool sub1 = 1;
		for (ll i = 1; i <= n; ++i)
		{
			sub1 &= (sz(g[i]) == 2);
		}
		if (sub1)
		{
			if (n % 4 == 0)
			{
				cout << n / 2 << nl;
			}
			else
			{
				cout << -1 << nl;
			}
		}
	}
}
 
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
//  freopen("spainting.in", "r", stdin);
//  freopen("spainting.out", "w", stdout);
    int ttt = 1;
//  cin >> ttt;
    for (int test = 1; test <= ttt; ++test)
    {
//      cout << "Case " << test << ":" << ' ';
        ma1n();
    }
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 40
• Subtask 4: 0 / 50