제출 #685845

#제출 시각아이디문제언어결과실행 시간메모리
685845SunbaeConnecting Supertrees (IOI20_supertrees)C++17
21 / 100
197 ms27896 KiB
#include <bits/stdc++.h>
#include "supertrees.h"
using namespace std;
vector<int>parent;
vector<int>Size;
int findUpar(int node){
    if(node == parent[node]) return node;
    return parent[node] = findUpar(parent[node]);
}
void Union(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];
    }
}
bool detectCycle(int src, vector<int> Adj[], vector<bool>&visited, int n){
    visited[src] = true;
    queue<pair<int,int>>q;
    q.push({src, -1});
    while(!q.empty()){
        int node = q.front().first;
        int par = q.front().second;
        q.pop();
        for(int adjNode: Adj[node]){
            if(!visited[adjNode]){
                visited[adjNode] = true;
                q.push({adjNode, node});
            }else if(par != adjNode){
                return true;
            }
        }
    }
    return false;
}
int construct(vector<vector<int>>p){
    vector<pair<int,int>>zero, two;
    int n = p.size(); Size.resize(n); parent.resize(n);
    for(int i = 0; i<n; i++) Size[i] = 1, parent[i] = i;
    vector<vector<int>>adj(n, vector<int>(n, 0));
    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){
                Union(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;
        }
    }
    //mark 2
    vector<int>Adj[n];
    for(pair<int,int> it: two){
        int u = it.first, v = it.second;
        int pu = findUpar(u), pv = findUpar(v);
        if(pu == pv) return 0;
        adj[pu][pv] = 1; adj[pv][pu] = 1;
        Adj[pu].push_back(pv); Adj[pv].push_back(pu);
    }
    //check cycle
    vector<bool>visited(n, false);
    int cnt = 0;
    for(int i = 0; i<n; i++){
        if(!visited[i]){
            bool cycle = detectCycle(i, Adj, visited, n);
            if(cycle){
                ++cnt;
            }
        }
    }
    if(cnt) return 0;
    //Union 2
    for(pair<int,int> it: two){
        Union(it.first, it.second);
    }
    //check 0
    for(pair<int,int> it: zero){
        int pu = findUpar(it.first), pv = findUpar(it.second);
        if(pu == pv) return 0;
    }
    build(adj); return 1;
}
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