Submission #603697

#	Time	Username	Problem	Language	Result	Execution time	Memory
603697		Tigryonochekk	Connecting Supertrees (IOI20_supertrees)	C++17	40 / 100	368 ms	73032 KiB

supertrees

#include <iostream>
#include "supertrees.h"
#include <vector>
#include <set>
using namespace std;
const int N = 1002;

vector<vector<int>> answer;
set<int> dsu[N];
vector<int> ds[N];
int com[N];

void dfs(int v) {
	for (auto to : dsu[v]) {
		if (com[to]) continue;
		com[to] = com[v];
		dfs(to);
	}
}

int construct(vector<vector<int>> p) {
	int n = p.size();
	answer.resize(n);
	for (int i = 0; i < n; i++) {
		answer[i].resize(n);
	}
	bool flag = true;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (j == i) continue;
			if (p[i][j]) {
				dsu[i].insert(j);
				ds[i].push_back(j);
			}
			if (p[i][j] == 2)
				flag = false;
		}
	}
	int k = 1;
	for (int i = 0; i < n; i++) {
		if (!com[i]) {
			com[i] = k++;
			dfs(i);
		}
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (j == i) continue;
			if (com[i] == com[j] && dsu[i].find(j) == dsu[i].end()) return 0;
			if (com[i] != com[j] && dsu[i].find(j) != dsu[i].end()) return 0;
		}
	}
	if(flag)
	for (int i = 0; i < n; i++) {
		if (com[i]) {
			com[i] = 0;
			for (int j : dsu[i]) {
				answer[i][j] = 1;
				answer[j][i] = 1;
				com[j] = 0;
			}
		}
	}
	else {
		for (int i = 0; i < n; i++) {
			if (com[i]) {
				if (ds[i].size() == 1) return 0;
				if (ds[i].size() == 0) continue;
				//cout << ds[i].size() << " " << dsu[i].size() << endl;
				answer[i][ds[i][0]] = 1;
				answer[ds[i][0]][i] = 1;
				answer[i][ds[i].back()] = 1;
				answer[ds[i].back()][i] = 1;
				com[i] = 0;
				for (int j = 0; j < ds[i].size() - 1; j++) {
					answer[ds[i][j]][ds[i][j + 1]] = 1;
					answer[ds[i][j + 1]][ds[i][j]] = 1;
					com[ds[i][j]] = 0;
				}
				com[ds[i].back()] = 0;
			}
		}
	}
	build(answer);
	return 1;
}

/*
3 
1 0 0 
0 1 1 
0 1 1 



4 
1 0 0 0 
0 1 2 2 
0 2 1 2 
0 2 2 1 

3 
1 0 0 
0 1 2 
0 2 1 
*/

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:75:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |     for (int j = 0; j < ds[i].size() - 1; j++) {
      |                     ~~^~~~~~~~~~~~~~~~~~

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