Submission #1291665

#	Time	Username	Problem	Language	Result	Execution time	Memory
1291665		gustavo_d	Connecting Supertrees (IOI20_supertrees)	C++20	21 / 100	103 ms	26252 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
using namespace std;

#define sz(v) (int)(v).size()

const int MAXN = 1000;

vector<int> adj[MAXN];
vector<pair<int, int>> eds;
bool vis[MAXN];

vector<int> comp;

void dfs(int v) {
	vis[v] = true;
	comp.push_back(v);
	for (int viz : adj[v]) {
		if (vis[viz]) continue;
		dfs(viz);
	}
}

int construct(vector<vector<int>> paths) {
	int n = sz(paths);

	for (int i=0; i<n; i++) {
		for (int j=0; j<n; j++) {
			if (i == j) continue;
			if (paths[i][j] == 0) continue;
			adj[i].push_back(j);
		}
	}

	for (int i=0; i<n; i++) {
		if (vis[i]) continue;
		comp.clear();
		dfs(i);
		for (int u : comp) {
			for (int v : comp) {
				if (paths[u][v] == 0) {
					// cerr << u << ' ' << v << " together\n"; 
					return 0;
				}
			}
		}

		if (sz(comp) == 1) continue;

		vector<int> g1, g2;
		for (int viz : adj[i]) {
			if (paths[i][viz] == 1) g1.push_back(viz);
			else g2.push_back(viz);
		}

		if (sz(g1) > 0) {
			if (paths[g1[0]][i] == 1) g1.push_back(i);
			else g2.push_back(i);
		} else {
			g2.push_back(i);
		}

		// cout << "componente\n";
		// for (int v : g1) cout << v << ' ';
		// cout << '\n';
		// for (int v : g2) cout << v << ' ';
		// cout << '\n';

		// verify
		for (int v : g1) {
			for (int u : g1) {
				if (u == v) continue;
				if (paths[u][v] == 2) {
					// cerr << 11 << ' ' << u << ' ' << v << '\n';
					return 0;
				}
			}
			for (int u : g2) {
				if (paths[u][v] == 1) {
					// cerr << 12 << ' ' << u << ' ' << v << '\n';
					return 0;
				}
			}
		}
		for (int v : g2) {
			for (int u : g2) {
				if (u == v) continue;
				if (paths[u][v] == 1) {
					// cerr << 22 << ' ' << u << ' ' << v << '\n';
					return 0;
				}
			}
		}

		for (int j=1; j<sz(g2); j++) {
			eds.emplace_back(g2[j-1], g2[j]);
		}
		for (int j=1; j<sz(g1); j++) {
			eds.emplace_back(g1[j-1], g1[j]);
		}
		if (!g1.empty() and !g2.empty()) {
			eds.emplace_back(g1[0], g2[0]);
			eds.emplace_back(g1[0], g2.back());
		}
	}

	vector<vector<int>> ans(n, vector<int> (n, 0));
	// cerr << sz(eds) << '\n';
	for (auto [u, v] : eds) {
		// cerr << u << ' ' << v << '\n';
		ans[u][v] = ans[v][u] = 1;
	}
	build(ans);
	return 1;
}

• Subtask 1: 11 / 11
• Subtask 2: 10 / 10
• Subtask 3: 0 / 19
• Subtask 4: 0 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4