Submission #689287

#	Time	Username	Problem	Language	Result	Execution time	Memory
689287		Sunbae	Connecting Supertrees (IOI20_supertrees)	C++17	0 / 100	1 ms	212 KiB

supertrees

#include <bits/stdc++.h>
#include "supertrees.h"
using namespace std;
vector<int> parent, Size;
int findUpar(int node){
    if(node == parent[node]) return node;
    return parent[node] = findUpar(parent[node]);
}
void U(int u, int v){
    int pu = findUpar(u), pv = findUpar(v);
    if(pu == pv) return;
    if(Size[pu] > Size[pv]){
        parent[pv] = pu;
        Size[pu] += Size[pv];
    }else{
        parent[pu] = pv;
        Size[pv] += Size[pu];
    }
}
int construct(vector<vector<int>>p){
    int n = p.size(); parent.resize(n); Size.resize(n);
    for(int i = 0; i<n; i++) parent[i] = i, Size[i] = 1;
    vector<vector<int>>adj(n, vector<int>(n, 0));
    vector<pair<int,int>>zero, two;
    for(int i = 0; i<n; i++){
        for(int j = 0; j<n; j++){
            if(p[i][j] == 0){
                zero.push_back({i, j});
            }else if(p[i][j] == 1){
                U(i, j);
            }else if(p[i][j] == 2){
                two.push_back({i, j});
            }else if(p[i][j] == 3){
                return 0;
            }
        }
    }
    //mark 1
    for(int i = 0; i<n; i++){
        int pi = findUpar(i);
        if(i != pi){
            adj[i][pi] = 1; adj[pi][i] = 1;
        }
    }
    //connect root-root
    set<int>s;
    for(pair<int,int> it: two){
        int pu = findUpar(it.first);
        int pv = findUpar(it.second);
        if(pu == pv) return 0;
        adj[pu][pv] = 1; adj[pv][pu] = 1;
        s.insert(pu);
        s.insert(pv);
    }
    if(s.size() <= 2) return 0;
    //making them the same component
    for(pair<int,int> it: two){
        U(findUpar(it.first), findUpar(it.second));
    }
    //check if in the same component (check zero)
    for(pair<int,int> it: zero){
        if(findUpar(it.first) == findUpar(it.second)) return 0;
    }
    build(adj); return 1;
}

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