Submission #1291662

#	Time	Username	Problem	Language	Result	Execution time	Memory
1291662		kahoul	Connecting Supertrees (IOI20_supertrees)	C++20	96 / 100	104 ms	22348 KiB

supertrees

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

const int maxn = 1e3 + 10;

struct uf {
	int parent[maxn];
	vector<int> member[maxn];

	void init (int n) {
		for (int i = 0; i < n; i++) {
			parent[i] = i;
			member[i].push_back(i);
		}
	}

	int find (int u) {
		if (parent[u] == u) return u;
		return parent[u] = find(parent[u]);
	}

	void onion (int u, int v) {
		u = find(u);
		v = find(v);
		if (u == v) return;
		if (u > v) swap(u, v);
		parent[v] = u;
		for (auto c : member[v]) {
			member[u].push_back(c);
		}
	}
};

int construct(vector<vector<int>> p) {
	int n = p.size();
	uf ones;
	uf twos;
	ones.init(n);
	twos.init(n);

	vector<vector<int>> answer;

	for (int i = 0; i < n; i++) {
		vector<int> row(n, 0);
		answer.push_back(row);
	}

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (p[i][j] == 2) {
				twos.onion(i, j);
			} else if (p[i][j] == 0) {
				if (twos.find(i) == twos.find(j)) return 0;
			}
		}
	}

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (p[i][j] == 1) {
				ones.onion(i, j);
			} else if (p[i][j] == 0) {
				if (ones.find(i) == ones.find(j)) return 0;
			}
		}
	}

	for (int i = 0; i < n; i++) {
		if (ones.parent[i] != i) continue;
		for (auto v : ones.member[i]) {
			answer[i][v] = 1;
			answer[v][i] = 1;
		}
	}

	vector<vector<int>> im_min(n);

	for (int i = 0; i < n; i++) {
		if (ones.parent[i] != i) continue;
		for (int j = 0; j < n; j++) {
			if (p[i][j] == 2) {
				im_min[j].push_back(i);
				break;
			}
		}
	}

	for (int i = 0; i < n; i++) {
		if (im_min[i].size() == 0) continue;
		vector<int> merge_min = im_min[i];

		for (auto c : im_min[i]) {
			if (im_min[c].size() > 0) {
				for (auto D : im_min[c]) {
					merge_min.push_back(D);
				}
			}
			im_min[c].clear();
		}

		if (merge_min.size() == 2) return 0;

		for (int j = 0; j < merge_min.size(); j++) {
			int cur = merge_min[j];
			int other = merge_min[(j + 1) % (merge_min.size())];
			answer[cur][other] = 1;
			answer[other][cur] = 1;
		}
	}

	for (int i = 0; i < n; i++) {
		answer[i][i] = 0;
	}

	build(answer);
	return 1;
}

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