Submission #1209273

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209273		bangan	Keys (IOI21_keys)	C++20	37 / 100	3094 ms	25916 KiB

keys

#include <bits/stdc++.h>

std::vector<int> find_reachable(std::vector<int> r, std::vector<int> u, std::vector<int> v, std::vector<int> c) {
	int n = r.size();
	int m = u.size();

	std::vector<std::vector<int>> adj(n);
	for (int i = 0; i < m; i++) {
		adj[u[i]].push_back(i);
		adj[v[i]].push_back(i);
	}

	std::vector<int> comp;
	std::vector<bool> vis(n), have(n);
	auto dfs = [&](auto self, int x) -> void {
		comp.push_back(x);
		vis[x] = true;
		have[r[x]] = true;
		for (int i : adj[x]) {
			int y = v[i] ^ u[i] ^ x;
			if (!vis[y] && have[c[i]]) {
				self(self, y);
			}
		}
	};

	std::vector<int> reach(n);
	for (int i = 0; i < n; i++) {
		int rep = 5;
		while (rep--) {
			comp.clear();
			dfs(dfs, i);
			for (int x : comp) {
				vis[x] = false;
			}
		}
		for (int x : comp) {
			have[r[x]] = false;
		}

		reach[i] = comp.size();
	}

	int min = *std::min_element(reach.begin(), reach.end());

	std::vector<int> ans(n);
	for (int i = 0; i < n; i++) {
		if (reach[i] == min) {
			ans[i] = 1;
		}
	}
	return ans;
}

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