Submission #377337

#	Time	Username	Problem	Language	Result	Execution time	Memory
377337		autumn_eel	Connecting Supertrees (IOI20_supertrees)	C++14	100 / 100	281 ms	22464 KiB

supertrees

#include "supertrees.h"

#include <bits/stdc++.h>
#define rep(i,n)for(int i=0;i<(int)(n);i++)
using namespace std;

struct UnionFind{
	vector<int>par;
	UnionFind(int n){
		par=vector<int>(n);
		rep(i,n)par[i]=i;
	}
	int find(int x){
		return par[x]==x?x:par[x]=find(par[x]);
	}
	void unite(int x,int y){
		x=find(x);y=find(y);
		par[y]=x;
	}
	bool same(int x,int y){
		return find(x)==find(y);
	}
};
static vector<int>v[2000],v2[2000];

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);
	}
	UnionFind uf1(n);
	rep(i,n)rep(j,n){
		if(p[i][j]==1)uf1.unite(i,j);
	}
	rep(i,n){
		v[uf1.find(i)].push_back(i);
	}
	UnionFind uf2(n);
	rep(i,n)for(int j=i+1;j<n;j++){
		if(!v[i].empty()&&!v[j].empty()&&p[i][j]==2){
			uf2.unite(i,j);
		}
	}
	rep(i,n){
		if(!v[i].empty())v2[uf2.find(i)].push_back(i);
	}
	rep(i,n){
		if(v2[i].size()>1){
			if(v2[i].size()==2)return 0;
			rep(j,v2[i].size()){
				answer[v2[i][j]][v2[i][(j+1)%v2[i].size()]]=1;
				answer[v2[i][(j+1)%v2[i].size()]][v2[i][j]]=1;
			}
		}
	}
	rep(i,n){
		if(v[i].size()>1){
			rep(j,v[i].size()-1){
				answer[v[i][j]][v[i][j+1]]=1;
				answer[v[i][j+1]][v[i][j]]=1;
			}
		}
	}
	rep(i,n)for(int j=i+1;j<n;j++){
		if(uf1.same(i,j)){
			if(p[i][j]!=1)return 0;
		}
		else if(uf2.same(uf1.find(i),uf1.find(j))){
			if(p[i][j]!=2)return 0;
		}
		else if(p[i][j]!=0)return 0;
	}
	build(answer);
	return 1;
}

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