Submission #301579

#	Time	Username	Problem	Language	Result	Execution time	Memory
301579		jwvg0425	Connecting Supertrees (IOI20_supertrees)	C++17	54 / 100	1064 ms	22296 KiB

supertrees

#include "supertrees.h"
#include <vector>
#include <set>

using namespace std;

int cpar[1005];
int tpar[1005];
vector<int> byTree[1005];

int tfind(int x)
{
	if (tpar[x] == x)
		return x;

	return tpar[x] = tfind(tpar[x]);
}

void tmerge(int x, int y)
{
	x = tfind(x);
	y = tfind(y);

	tpar[x] = y;
}

int cfind(int x)
{
	if (cpar[x] == x)
		return x;

	return cpar[x] = cfind(cpar[x]);
}

void cmerge(int x, int y)
{
	x = cfind(x);
	y = cfind(y);

	cpar[x] = y;
}

int construct(vector<vector<int>> p)
{
	int n = p.size();

	for (int i = 0; i < n; i++)
		cpar[i] = tpar[i] = i;

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

	for (int i = 0; i < n; i++)
	{
		for (int j = i + 1; j < n; j++)
		{
			if (p[i][j] == 0)
				continue;

			if (p[i][j] == 1)
			{
				if (tfind(i) == tfind(j))
					continue;

				tmerge(i, j);
				answer[i][j] = answer[j][i] = 1;
				continue;
			}

			if (p[i][j] >= 2)
				cmerge(i, j);
		}
	}

	for (int i = 0; i < n; i++)
	{
		byTree[tfind(i)].push_back(i);
		for (int j = i + 1; j < n; j++)
		{
			if (p[i][j] == 0)
			{
				if (cfind(i) == cfind(j) || tfind(i) == tfind(j))
					return 0;
			}

			if (p[i][j] == 1)
			{
				if (tfind(i) != tfind(j))
					return 0;
			}

			if (p[i][j] >= 2)
			{
				if (cfind(i) != cfind(j) || tfind(i) == tfind(j))
					return 0;
			}
		}
	}

	for (int i = 0; i < n; i++)
	{
		if (cfind(i) != i)
			continue;

		vector<int> cs;
		set<int> ts;

		for (int j = 0; j < n; j++)
		{
			if (cfind(j) != i)
				continue;

			cs.push_back(j);
			ts.insert(tfind(j));
		}

		set<int> cv;
		vector<int> tv;
		for (auto ti : ts)
		{
			tv.push_back(ti);

			for (auto &x : byTree[ti])
				for (auto &y : byTree[ti])
					if (p[x][y] != 1)
						return 0;

			for (auto &tj : ts)
			{
				if (ti == tj)
					continue;

				for (auto &x : byTree[ti])
					for (auto &y : byTree[tj])
						cv.insert(p[x][y]);
			}
		}

		int k = tv.size();

		if (k <= 1)
			continue;

		if (k == 2)
			return 0;

		if (cv.size() >= 2 || *cv.begin() < 2)
			return 0;

		for (int x = 0; x < k; x++)
		{
			int nx = (x + 1) % k;
			answer[tv[x]][tv[nx]] = answer[tv[nx]][tv[x]] = 1;
		}

		if (*cv.begin() == 3)
			answer[tv[0]][tv[2]] = answer[tv[2]][tv[0]] = 1;
	}

	build(answer);
	return 1;
}

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