Submission #788704

#	Time	Username	Problem	Language	Result	Execution time	Memory
788704		thimote75	Keys (IOI21_keys)	C++17	37 / 100	3060 ms	29648 KiB

keys

#include <bits/stdc++.h>

using namespace std;

using idata = vector<int>;
using igrid = vector<idata>;
using t_road = pair<int, int>;
using t_roads = vector<t_road>;
using t_graph = vector<t_roads>;
using bdata = vector<bool>;

int N, M;

t_graph roads;
t_graph roads_by_key;

idata key_type;

int compute (int node) {
	bdata keys_found(N);
	bdata node_visit(N);

	queue<int> nodes;
	int size = 0;
	nodes.push(node); node_visit[node] = true;

	while (nodes.size() != 0) {
		size ++;
		int curr = nodes.front(); nodes.pop();

		for (const auto &road : roads[curr]) {
			int type = road.second; int next = road.first;
			if (!keys_found[type]) continue ;
			if (node_visit[next]) continue ;
			node_visit[next] = true;
			nodes.push(next);
		}

		if (keys_found[key_type[curr]]) continue ;
		keys_found[key_type[curr]] = true;

		for (const auto &road : roads_by_key[key_type[curr]]) {
			int a = road.first; int b = road.second;

			if (!(node_visit[a] ^ node_visit[b])) continue ;
			int next = node_visit[a] ? b : a;

			node_visit[next] = true;
			nodes.push(next);
		}
	}

	return size;
}

idata find_reachable(idata r, idata u, idata v, idata c) {
	N = r.size();
	M = u.size();

	key_type = r;
	roads.resize(N);
	roads_by_key.resize(N);

	for (int i = 0; i < M; i ++) {
		roads[u[i]].push_back({ v[i], c[i] });
		roads[v[i]].push_back({ u[i], c[i] });

		roads_by_key[c[i]].push_back({ u[i], v[i] });
	}

	idata ans(N);
	for (int i = 0; i < N; i ++) ans[i] = compute(i);

	int mn = 1e9;
	for (int u : ans) mn = min(mn, u);
	for (int i = 0; i < N; i ++)
		ans[i] = ans[i] == mn;

	return ans;
}

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 17 / 17
• Subtask 4: 0 / 30
• Subtask 5: 0 / 33