Submission #1002313

#	Time	Username	Problem	Language	Result	Execution time	Memory
1002313		toast12	Connecting Supertrees (IOI20_supertrees)	C++14	19 / 100	136 ms	24148 KiB

supertrees

#include "supertrees.h"
#include <vector>
#include <map>
#include <iostream>
using namespace std;

struct DSU {
	int n;
	vector<int> link, size;
	DSU(int sz) {
		n = sz;
		link.resize(sz);
		size.resize(sz);
		for (int i = 0; i < n; i++) {
			link[i] = i;
			size[i] = 1;
		}
	}
	int find(int x) {
		while (x != link[x])
			x = link[x];
		return x;
	} 
	bool same(int a, int b) {
		return find(a) == find(b);
	}
	void unite(int a, int b) {
		a = find(a);
		b = find(b);
		if (a == b)
			return;
		if (size[a] < size[b])
			swap(a, b);
		link[b] = a;
		size[a] += size[b];
	}
};

int construct(std::vector<vector<int>> p) {
	int n = p.size();
	vector<vector<int>> answer(n, vector<int>(n));
	vector<vector<int>> c(n);
	DSU d(n+1);
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (i == j)
				continue;
			if (p[i][j]) {
				if (!d.same(i, j)) {
					d.unite(i, j);
					int x = d.find(i);
					c[x].push_back(j);
					c[x].push_back(i);
				}
			}
		}
	}
	// for (int i = 0; i < n; i++) {
	// 	cout << i << ": ";
	// 	for (auto x : c[i])
	// 		cout << x << ' ';
	// 	cout << '\n';
	// }
	for (int i = 0; i < n; i++) {
		if (c[i].empty())
			continue;
		if (c[i].size() == 2)
			return 0;
		vector<bool> done(n);
		vector<int> x;
		for (int j = 0; j < (int)c[i].size(); j++) {
			if (!done[c[i][j]])
				x.push_back(c[i][j]);
         	done[c[i][j]] = true;
			for (int k = j+1; k < (int)c[i].size(); k++) {
				if (!p[c[i][j]][c[i][k]])
					return 0;
			}
		}
		for (int j = 0; j < (int)x.size()-1; j++) {
			answer[x[j]][x[j+1]] = 1;
			answer[x[j+1]][x[j]] = 1;
		}
		answer[x[0]][x.back()] = 1;
		answer[x.back()][x[0]] = 1;
	}
	build(answer);
	return 1;
}

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