Submission #300357

#	Time	Username	Problem	Language	Result	Execution time	Memory
300357		oolimry	Connecting Supertrees (IOI20_supertrees)	C++14	100 / 100	272 ms	26232 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
#define all(x) (x).begin() (x).end()
#define sz(x) (int) (x).size()
using namespace std;
typedef vector<vector<int>> vvi;

int n;
vector<vector<int>> die = {{-1}};

struct ufds{
	int p[1005];
	int n;
	void init(int N ){
		n = N;
		for(int i = 0;i <= n;i++) p[i] = i;
	}
	
	int findSet(int u){
		if(u == p[u]) return u;
		else{
			p[u] = findSet(p[u]);
			return p[u];
		}
	}
	
	void unionSet(int u, int v){
		u = findSet(u);
		v = findSet(v);
		
		if(u == v) return;
		if(u&v) swap(u,v);
		p[u] = v;
	}
	
	bool isSameSet(int u, int v){
		return findSet(u) == findSet(v);
	}
};
vector<vector<int>> adj;

vector<vector<int>> decomp1(){
	int good = 1, bad = 0;
	
	ufds uf; uf.init(n);
	
	for(int i = 0;i < n;i++) for(int j = 0;j < n;j++){
		if(adj[i][j] >= good) uf.unionSet(i, j);
	}
	
	for(int i = 0;i < n;i++) for(int j = 0;j < n;j++){
		if(adj[i][j] >= good){
			if(!uf.isSameSet(i,j)) return die;
		}
		else if(adj[i][j] <= bad){
			if(uf.isSameSet(i,j)) return die;
		}
	}
	
	map<int,vector<int> > M;
	for(int i = 0;i < n;i++){
		int u = uf.findSet(i);
		M[u].push_back(i);
	}
	
	vvi res;
	for(auto x : M){
		res.push_back({});
		for(int y : x.second) res.back().push_back(y);
	}
	
	return res;
}
ufds uf2;

vvi decomp2(vector<int> A){
	int good = 1, bad = 2;
	
	for(int i : A) for(int j : A){
		if(adj[i][j] == 1) uf2.unionSet(i, j);
	}
	
	for(int i : A) for(int j : A){
		if(adj[i][j] == 1){
			if(!uf2.isSameSet(i,j)) return die;
		}
		else if(adj[i][j] == 2){
			if(uf2.isSameSet(i,j)) return die;
		}
	}
	
	map<int,vector<int> > M;
	for(int i : A){
		int u = uf2.findSet(i);
		M[u].push_back(i);
	}
	
	vvi res;
	for(auto x : M){
		res.push_back({});
		for(int y : x.second) res.back().push_back(y);
	}
	
	return res;
}

int construct(vector<vector<int>> ADJ) {
	adj = ADJ;
	
	n = adj.size();
	vector<vector<int> > answer;
	for (int i = 0; i < n; i++) {
		std::vector<int> row;
		row.resize(n);
		answer.push_back(row);
	}
	
	for(auto x : ADJ) for(int y : x){
		if(y == 3) return 0;
	}
	
	vvi res = decomp1();
	
	if(res == die) return 0;
	
	uf2.init(n);
	
	for(vector<int> x : res){
		vvi res2 = decomp2(x);
		
		if(sz(res2) == 2) return 0;
		
		for(auto line : res2){
			for(int i = 1;i < sz(line);i++){
				int a = line[i-1], b = line[i];
				answer[a][b] = 1;
				answer[b][a] = 1;
			}
		}
		
		if(sz(res2) > 2){
			for(int i = 0;i < sz(res2);i++){
				int j = i+1; if(j == sz(res2)) j = 0;
				
				int a = res2[i].back(), b = res2[j].back();
				answer[a][b] = 1;
				answer[b][a] = 1;
			}
		}
		//cout << "F\n\n";
	}
	
	for(int i = 0;i < n;i++) answer[i][i] = 0;
	
	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'vvi decomp2(std::vector<int>)':
supertrees.cpp:77:6: warning: unused variable 'good' [-Wunused-variable]
   77 |  int good = 1, bad = 2;
      |      ^~~~
supertrees.cpp:77:16: warning: unused variable 'bad' [-Wunused-variable]
   77 |  int good = 1, bad = 2;
      |                ^~~

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