Submission #1239868

#	Time	Username	Problem	Language	Result	Execution time	Memory
1239868		lunarecho	Connecting Supertrees (IOI20_supertrees)	C++20	21 / 100	118 ms	22148 KiB

supertrees

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

struct DSU {

    vector<int> parent;
    
    void init(int n)
    {
        parent.resize(n);
        for(int i=0;i<n;++i)
            parent[i] = i;
    }

    int find(int x)
    {
    	if(parent[x] != x)
    		parent[x] = find(parent[x]);
    	return parent[x];
    }

    void unite(int a,int b)
    {
    	int u = find(a), v = find(b);
    	if(u != v)
    	{
    		parent[u] = v;
    	}
    }

};

int construct(vector<vector<int>> p) {
	
	int n = p.size();
    if(n == 1)
    {
        build({{0}});
        return 1;
    }
    DSU d;
    d.init(n);
    for(int i=0;i<n;++i)
    {
        for(int j=i+1;j<n;++j)
        {
            if(p[i][j] == 1)
            {
                d.unite(i,j);
            }
        }
    }
    for(int i=0;i<n;++i)
    {
        for(int j=i+1;j<n;++j)
        {
            if(p[i][j] == 0 && d.find(i) == d.find(j))
            	return 0;
            else if(p[i][j] == 1 && d.find(i) != d.find(j))
            	return 0; 
        }
    }

    vector<vector<int>> ans(n,vector<int>(n));

    map<int,vector<int>> helping;

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

    for(auto &it : helping)
    {
    	vector<int> v = it.second;
    	for(int i=1;i<(int)v.size();++i)
    	{
    		int u = v[i-1], vv = v[i];
    		ans[u][vv] = 1;
    		ans[vv][u] = 1;
    	}
   	}

    build(ans);
    
    return 1;
}

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