Submission #630072

#	Time	Username	Problem	Language	Result	Execution time	Memory
630072		ttamx	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	591 ms	71084 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>

using namespace std;

vector<vector<int>> ans;
vector<int> adj[1005];
set<int> adj2[1005];
int pa[1005],pa2[1005];
int np[1005][1005];
bool vis[1005];

int fp(int u){
    if(pa[u]==u)return u;
    return pa[u]=fp(pa[u]);
}

void dfs(int u,int r){
    vis[u]=1;
    for(auto v:adj2[u]){
        if(vis[v])continue;
        pa[fp(u)]=fp(v);
        ans[u][v]=ans[v][u]=1;
        dfs(v,r);
        return;
    }
    if(u!=r)ans[u][r]=ans[r][u]=1;
}

int construct(vector<vector<int>> p) {
	int n = p.size();
	for (int i = 0; i < n; i++) {
		vector<int> row;
		row.resize(n);
		ans.push_back(row);
	}
	iota(pa,pa+n,0);
	for(int i=0;i<n;++i)for(int j=0;j<n;++j)if(p[i][j]==3)return 0;
	for(int i=0;i<n;++i)for(int j=0;j<n;++j)if(p[i][j]==1)pa[fp(i)]=fp(j);
	for(int i=0;i<n;++i)adj[fp(i)].emplace_back(i);
	for(int i=0;i<n;++i)for(auto j:adj[i])if(i!=j)ans[i][j]=ans[j][i]=1;
	for(int i=0;i<n;++i)pa2[i]=pa[i];
	for(int i=0;i<n;++i){
        int cnt=0;
        for(int j=0;j<n;++j)if(p[i][j]==2){
            ++cnt;
            adj2[pa2[i]].insert(pa2[j]);
            adj2[pa2[j]].insert(pa2[i]);
        }
        if(cnt==1)return 0;
	}
	for(int i=0;i<n;++i)if(i==pa2[i])if(!vis[i])dfs(i,i);
	for(int i=0;i<n;++i)fp(i);
	for(int i=0;i<n;++i)for(int j=0;j<n;++j)if(ans[i][j]==1)np[pa[i]][pa[j]]=1;
	for(int i=0;i<n;++i)for(int j=0;j<n;++j){
        if(i==j)continue;
        if(pa[i]==pa[j]&&p[i][j]==0)return 0;
        if(pa2[i]==pa2[j]&&p[i][j]!=1)return 0;
        if(pa[i]==pa[j]&&pa2[i]!=pa2[j]&&p[i][j]!=2)return 0;
        if(pa[i]!=pa[j]&&p[i][j]!=0)return 0;
        if(np[pa[i]][pa[j]]==1&&p[i][j]==0)return 0;
        if(np[pa[i]][pa[j]]==0&&p[i][j]!=0)return 0;
	}
	build(ans);
	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