Submission #838665

#	Time	Username	Problem	Language	Result	Execution time	Memory
838665		SoulKnight	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	174 ms	22168 KiB

supertrees

#include "supertrees.h"
#include <vector>
#include <iostream>
#include <numeric>
#include <cstring>

using namespace std;

#define ll long long
#define ln '\n'

const int N = 1000 + 5;

int par[N], who[N];
vector<int> com[N];


int find(int u){return ((u == par[u])? u: par[u]=find(par[u]));}



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

	iota(par, par+n, 0);
	memset(who, -1, sizeof(who));

	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] == 3) return 0;
			par[find(i)] = find(j);
		}
	}

	for (int i = 0; i < n; i++){
		com[find(i)].push_back(i);
	}


	for (int i = 0; i < n; i++){
		if (com[i].size() <= 1) continue;

		vector<int> cycle;
		bool has3 = false, has2 = false;

		for (auto& v: com[i]){
			vector<int> line; line.push_back(v);
			for (auto& j: com[i]){
				if (v == j) continue;
				if (p[v][j] == 2) {has2 = true; continue;}
				if (p[v][j] == 3) {has3 = true; continue;}
				if (p[j][v] == 0) return 0;
				if (who[j] != who[v]) return 0;


				if (who[j] == -1) who[j] = v;
				line.push_back(j);
			}

			if (has2 && has3) return 0;

			if (who[v] == -1) {
				who[v] = v;
				cycle.push_back(v);
				for (int k = 1; k < line.size(); k++) {
					answer[line[k]][line[k-1]] = answer[line[k-1]][line[k]] = 1;
				}
			}
		}

		if (cycle.size() == 1) continue;
		if (cycle.size() == 2) return 0;

		for (int i = 1; i < cycle.size(); i++){
			answer[cycle[i-1]][cycle[i]] = answer[cycle[i]][cycle[i-1]] = 1;
		}
		answer[cycle.front()][cycle.back()] = answer[cycle.back()][cycle.front()] = 1;

		if (has3){
			if (cycle.size() == 3) return 0;

			answer[cycle[0]][cycle[cycle.size()-2]] = 1;
			answer[cycle[cycle.size()-2]][cycle[0]] = 1;
		}

	}


	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:72:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |     for (int k = 1; k < line.size(); k++) {
      |                     ~~^~~~~~~~~~~~~
supertrees.cpp:81:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   81 |   for (int i = 1; i < cycle.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