Submission #829701

#	Time	Username	Problem	Language	Result	Execution time	Memory
829701		faruk	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	190 ms	26828 KiB

supertrees

#include "supertrees.h"
#include <iostream>
#include <vector>
#include <algorithm>
#define mp make_pair
#define all(a) a.begin(), a.end()

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

vector<vector<int> > out;

int n;
bool check_components(vector<vector<int> > p) {
	vector<int> comp(n, -1);
	for (int i = 0; i < n; i++) {
		if (p[i][i] != 1)
			return false;
		if (comp[i] == -1) {
			for (int j = 0; j < n; j++) {
				if (p[i][j] != 0 and comp[j] != -1)
					return false;
				if (p[i][j] != 0)
					comp[j] = i;
			}
		}
		else {
			for (int j = 0; j < n; j++)
				if (p[i][j] != 0 and comp[j] != comp[i])
					return false;
		}
	}
	return true;
}

void make_line(vector<int> a) {
	if (a.size() == 1)
		return;
	for (int i = 0; i < a.size() - 1; i++)
	{
		int f = a[i], s = a[i + 1];
		out[f][s] = 1, out[s][f] = 1;
	}
}
vector<vector<int> > p;
vector<bool> vis;
vector<int> ch;
void dfs(int c) {
	ch.push_back(c);
	vis[c] = true;
	for (int i = 0; i < n; i++) {
		if (p[i][c] == 1 and !vis[i])
			dfs(i);
	} 
}

int construct(std::vector<std::vector<int>> p) {
	n = p.size();
	::p = p;
	std::vector<std::vector<int>> answer;
	if (check_components(p) == false)
		return 0;
	vector<bool> visited(n);
	out = vector<vector<int> >(n, vector<int>(n, 0));
	for (int v = 0; v < n; v++) {
		if (visited[v])
			continue;
		vector<int> mine;
		for (int j = 0; j < n; j++)
			if (p[v][j] != 0)
				mine.push_back(j), visited[j] = true;
		if (mine.size() == 1)
			continue;

		vector<int> everyone_else = mine;
		vector<vector<int> > chains;
		vis = vector<bool>(n);
		for (int a : everyone_else) {
			// now we decompose into sub-chains
			ch.clear();
			if (!vis[a]) {
				dfs(a);
				chains.push_back(ch);
			}
		}

		// now check if chains are good
		for (int i = 0; i < chains.size(); i++) {
			for (int a : chains[i])
				for (int b : chains[i])
					if (p[a][b] != 1)
						return 0;
			for (int j = i + 1; j < chains.size(); j++) {
				for (int a : chains[i])
					for (int b : chains[j])
						if (p[a][b] != 2)
							return 0;
			}
		}

		for (vector<int> chai : chains)
			make_line(chai);
		// connecting chains and cyc
		if (chains.size() > 1) {
			vector<int> fin;
			for (int i = 0; i < chains.size(); i++)
				fin.push_back(chains[i][0]); 
			fin.push_back(chains[0][0]);
			if (chains.size() == 2)
				return 0;
			make_line(fin);
		}
	}
	build(out);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'void make_line(std::vector<int>)':
supertrees.cpp:41:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |  for (int i = 0; i < a.size() - 1; i++)
      |                  ~~^~~~~~~~~~~~~~
supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:90:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   90 |   for (int i = 0; i < chains.size(); i++) {
      |                   ~~^~~~~~~~~~~~~~~
supertrees.cpp:95:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   95 |    for (int j = i + 1; j < chains.size(); j++) {
      |                        ~~^~~~~~~~~~~~~~~
supertrees.cpp:108:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  108 |    for (int i = 0; i < chains.size(); i++)
      |                    ~~^~~~~~~~~~~~~~~

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