Submission #829670

#	Time	Username	Problem	Language	Result	Execution time	Memory
829670		faruk	Connecting Supertrees (IOI20_supertrees)	C++17	11 / 100	177 ms	26576 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 i = 0; i < n; i++) {
		if (visited[i])
			continue;
		vector<int> mine;
		for (int j = 0; j < n; j++)
			if (p[i][j] != 0)
				mine.push_back(j), visited[j] = true;
		if (mine.size() == 1)
			continue;

		vector<int> all2, everyone_else;
		for (int a : mine) {
			bool has1 = false;
			for (int j : mine)
				if (p[a][j] == 1 and j != a)
					has1 = true;
			if (has1)
				everyone_else.push_back(a);
			else
				all2.push_back(a);
		}
		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 j = i+1; j < chains.size(); j++) {
				for (int a : chains[i])
					for (int b : chains[j])
						if (p[a][b] != 2)
							return 0;
			}
		}

		if (everyone_else.size() == 0) { // cycle
			if (all2.size() <= 2)
				return 0;
			for (int i = 0; i < all2.size(); i++)
			{
				int f = all2[i], s = i < (all2.size() - 1) ? all2[i + 1] : all2[0];
				out[f][s] = 1, out[s][f] = 1;
			}
		}
		else if (all2.size() == 0) {// line
			make_line(everyone_else);
		}
		else {
			// made cycle chain
			if (all2.size() + chains.size() <= 2)
				return 0;
			make_line(all2);

			// made one chain
			for (vector<int> chai : chains)
				make_line(chai);

			// connecting chains and cyc
			vector<int> fin = { all2[0] };
			for (int i = 0; i < chains.size(); i++)
				fin.push_back(chains[i][0]);
			fin.push_back(all2.back());
			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:100:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  100 |   for (int i = 0; i < chains.size(); i++) {
      |                   ~~^~~~~~~~~~~~~~~
supertrees.cpp:101:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  101 |    for (int j = i+1; j < chains.size(); j++) {
      |                      ~~^~~~~~~~~~~~~~~
supertrees.cpp:112:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  112 |    for (int i = 0; i < all2.size(); i++)
      |                    ~~^~~~~~~~~~~~~
supertrees.cpp:114:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  114 |     int f = all2[i], s = i < (all2.size() - 1) ? all2[i + 1] : all2[0];
      |                          ~~^~~~~~~~~~~~~~~~~~~
supertrees.cpp:133:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  133 |    for (int i = 0; i < chains.size(); i++)
      |                    ~~^~~~~~~~~~~~~~~

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