Submission #930674

#	Time	Username	Problem	Language	Result	Execution time	Memory
930674		Cutebol	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	168 ms	24232 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
using namespace std;

const int N = 1003 ;
const int inf = 1e9 ;

int pr[N] , sz[N] , vis[N] ;
vector <int> vec[N] ;

int find ( int a ){
	if ( a == pr[a] ) return a ;
	return pr[a] = find(pr[a]) ;
}

void merge ( int a , int b ){
	a = find(a) ;
	b = find(b) ;
	if ( a != b ){
		if ( sz[a] > sz[b] ) swap(a,b) ;
		sz[b] += sz[a] ;
		pr[a] = b ;
	}
}

int construct(vector<vector<int>> p) {
	int n = p.size();
	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 ++ ) pr[i] = i , sz[i] = 1 ;
	for ( int i = 0 ; i < n ; i ++ ){
		for ( int j = 0 ; j < n ; j ++ ){
			if ( p[i][j] && i != j ){
				if ( p[i][j] == 3 ) return 0 ;
				merge(i,j) ;
			}
		}
	}
	for ( int i = 0 ; i < n ; i ++ ){
		for ( int j = 0 ; j < n ; j ++ ){
			if ( p[i][j] == 0 && find(i) == find(j) ) return 0 ;
		}
	}
	for ( int i = 0 ; i < n ; i ++ ) vec[find(i)].push_back(i) ;
	for ( int i = 0 ; i < n ; i ++ ) pr[i] = i , sz[i] = 1 ;
	for ( vector <int> v : vec ){
		for ( auto i : v ){
			for ( auto j : v ){
				if ( p[i][j] == 1 ) merge(i,j) ;
			}
		}
		for ( auto i : v ){
			for ( auto j : v ){
				if ( p[i][j] == 2 && find(i) == find(j) ) return 0 ;
			}
		}
		vector <int> b ;
		for ( auto i : v ){
			if ( find(i) != i ){
				answer[i][find(i)] = 1 ;
				answer[find(i)][i] = 1 ;
			}
			if ( !vis[find(i)] ){
				vis[find(i)] = 1 ;
				b.push_back(find(i)) ;
			}
		}
		if ( b.size() == 2 && p[b[0]][b[1]] == 2 ) return 0 ;
		for ( int i = 1 ; i < b.size() ; i ++ ){
			answer[b[i]][b[i-1]] = 1 ;
			answer[b[i-1]][b[i]] = 1 ;
		}
		if ( b.size() > 1 ){
			answer[b[0]][b[b.size()-1]] = 1 ;
			answer[b[b.size()-1]][b[0]] = 1 ;
		}
	}
	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:73:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |   for ( int i = 1 ; i < b.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