Submission #1291715

#	Time	Username	Problem	Language	Result	Execution time	Memory
1291715		gustavo_d	Connecting Supertrees (IOI20_supertrees)	C++20	100 / 100	102 ms	26264 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], vis2[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;
				}
			}
		}
        
        vector<vector<int>> grps;
        for (int v : comp) {
            if (vis2[v]) continue;
            vector<int> grp {v};
            for (int u : comp) {
                if (u == v) continue;
                if (paths[u][v] == 1) grp.push_back(u);
            }
            for (int a : grp) {
                vis2[a] = true;
                for (int b : grp) {
                    if (paths[a][b] != 1) return 0;
                }
            }
            grps.push_back(grp);
        }

        // cerr << "componentes:\n";
        // for (int g=0; g<sz(grps); g++) {
        //     for (int i=0; i<sz(grps[g]); i++) {
        //         cout << grps[g][i] << ' ';
        //     }
        //     cout << '\n';
        // }

        if (sz(grps) == 1) {
            for (int i=1; i<sz(grps[0]); i++) {
                eds.emplace_back(grps[0][i-1], grps[0][i]);
            }
            continue;
        }
        if (sz(grps) == 2) return 0;
        for (int g=0; g<sz(grps); g++) {
            for (int v : grps[g]) {
                for (int g2=g+1; g2<sz(grps); g2++) {
                    for (int u : grps[g2]) {
                        if (paths[u][v] != 2) return 0;
                    }
                }
            }
            for (int i=1; i<sz(grps[g]); i++) {
                eds.emplace_back(grps[g][i-1], grps[g][i]);
            }
            eds.emplace_back(grps[g][0], grps[(g+1) % sz(grps)][0]);
        }
	}

	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: 19 / 19
• Subtask 4: 35 / 35
• Subtask 5: 21 / 21
• Subtask 6: 4 / 4