Submission #1065701

#	Time	Username	Problem	Language	Result	Execution time	Memory
1065701		raspy	Closing Time (IOI23_closing)	C++17	0 / 100	100 ms	39736 KiB

closing

#include "closing.h"

#include <vector>
#include <queue>
#include <iostream>
#define ll long long
#define vi vector<ll>
#define pb push_back
#define ii pair<ll, ll>
#define f first
#define s second
#define inf 1'000'000'000'000'000'000

using namespace std;

vector<ii> graf[200005];
vi dis1, dis2;

void dfs(ll u, vi& dis, ll p = -1)
{
	for (auto [v, w]:graf[u])
	{
		if (v == p) continue;
		dis[v] = dis[u]+w;
		dfs(v, dis, u);
	}
}

ll sol1(ll n, ll x, ll y, ll k)
{
	priority_queue<ll, vi, greater<ll>> pq;
	for (ll i = 0; i < n; i++)
		pq.push(dis2[i]);
	ll tk = 0;
	ll rez = 0;
	while (pq.size() && tk+pq.top() <= k)
	{
		tk+=pq.top();
		pq.pop();
		rez++;
	}
	return rez;
}

ll sol2(ll n, ll x, ll y, ll k)
{
	priority_queue<ii, vector<ii>, greater<ii>> pq;
	priority_queue<ii, vector<ii>, greater<ii>> pq1;
	int tk = 0;
	int rez = 0;
	vi dod(n);
	for (int i = 0; i < n; i++)
	{
		if (dis1[i]+dis2[i] == dis1[x])
		{
			rez++;
			tk += dis2[i];
			pq.push({dis1[i]-dis2[i], i});
		}
		else
		{
			pq.push({dis2[i], i});
			pq1.push({dis1[i], i});
		}
	}
	if (tk > k)
		return 0;
	while (pq1.size() && tk+pq1.top().f <= k)
	{
		while (pq1.size() && dod[pq1.top().s])
			pq1.pop();
		if (pq1.empty())
			break;
		while (pq.size() && dod[pq.top().s])
			pq.pop();
		if (pq.size() <= 1)
		{
			rez+=2;
			// cout << "-> " << pq1.top().s << "\n";
			pq1.pop();
			continue;
		}
		ii pqt = pq.top();
		pq.pop();
		while (pq.size() && dod[pq.top().s])
			pq.pop();
		if (pq.size() && (pqt.f+pq.top().f < pq1.top().f))
		{
			dod[pqt.s] = 1;
			tk += pqt.f;
			// cout << "-> " << pqt.s << "\n";
			rez++;
			continue;
		}
		pq.push(pqt);
		rez+=2;
		tk += pq1.top().f;
		// cout << "-> " << pq1.top().s << "\n";
		dod[pq.top().s] = 1;
		pq1.pop();
	}
	while (pq.size() && tk+pq.top().first <= k)
	{
		while (pq.size() && dod[pq.top().s])
			pq.pop();
		if (pq.empty()) break;
		auto [d, u] = pq.top();
		pq.pop();
		tk+=d;
		if (!dod[u])
			pq.push({dis1[u]-dis2[u], u});
		dod[u] = 1;
		rez++;
	}
	return rez;
}

int max_score(int n, int x, int y, long long k, vector<int> U, vector<int> V, vector<int> W)
{
	for (ll i = 0; i < n; i++)
		graf[i].clear();
	dis1.clear();
	dis2.clear();
	dis1 = dis2 = vi(n, 0);
	for (ll i = 0; i < n-1; i++)
	{
		graf[U[i]].pb({V[i], W[i]});
		graf[V[i]].pb({U[i], W[i]});
	}
	dfs(x, dis1);
	dfs(y, dis2);
	for (ll i = 0; i < n; i++)
		if (dis1[i] < dis2[i])
			swap(dis1[i], dis2[i]);
	ll rez = sol1(n, x, y, k);
	rez = max(rez, sol2(n, x, y, k));
	return rez;
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 8
• Subtask 2: 0 / 9
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 9
• Subtask 6: 0 / 11
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 17