Submission #720655

#	Time	Username	Problem	Language	Result	Execution time	Memory
720655		Toxtaq	Connecting Supertrees (IOI20_supertrees)	C++17	11 / 100	177 ms	22032 KiB

supertrees

#ifndef SUPERTREES_H_INCLUDED
#define SUPERTREES_H_INCLUDED
#include "supertrees.h"
#include<bits/stdc++.h>
using namespace std;
struct DSU{
    vector<int>par;
    DSU(int n){
        par.assign(n, -1);
    }
    int FindRep(int u){
        if(par[u] < 0)return u;
        return par[u] = FindRep(par[u]);
    }
    void Union(int u, int v){
        u = FindRep(u);
        v = FindRep(v);
        if(u == v)return;
        if(par[u] > par[v])swap(u, v);
        par[u] += par[v];
        par[v] = u;
    }
    bool IsConnected(int u, int v){
        u = FindRep(u);
        v = FindRep(v);
        return (u == v);
    }
};
void build(vector<vector<int>>b);
int construct(vector<vector<int>>p){
    int n = p.size();
    vector<vector<int>>ans(n, vector<int>(n));
    DSU dsu1(n);
    vector<int>oneortwo(n);
    for(int i = 0;i < n;++i){
        int cnt = 0;
        for(int j = 0;j < n;++j){
            if(i != j && p[i][j])dsu1.Union(i, j);
            cnt += (p[i][j] == 1);
        }
        if(cnt == 1)oneortwo[i] = 2;
        else oneortwo[i] = 1;
    }
    vector<bool>chosen(n);
    for(int i = 0;i < n;++i){
        int par = dsu1.FindRep(i);
        if(chosen[i])continue;
        vector<int>ones, twos;
        for(int j = 0;j < n;++j){
            int node = dsu1.FindRep(j);
            if(dsu1.FindRep(j) == par){
                chosen[j] = 1;
                if(oneortwo[j] == 2)twos.push_back(j);
                else ones.push_back(j);
            }
        }
//        cout << i << ": \n";
//        cout << "ones: ";
//        for(int j : ones)cout << j << " ";
//        cout << "\ntwos: ";
//        for(int j : twos)cout << j << " ";
//        cout << '\n';
        for(int j = 1;j < ones.size();++j){
            ans[ones[j - 1]][ones[j]] = 1;
            ans[ones[j]][ones[j - 1]] = 1;
        }
        for(int j = 1;j < twos.size();++j){
            ans[twos[j - 1]][twos[j]] = 1;
            ans[twos[j]][twos[j - 1]] = 1;
        }
        if(!ones.size() && (int)twos.size() > 1){
            ans[twos[0]][twos.back()] = ans[twos.back()][twos[0]] = 1;
        }
        else if(ones.size() && (int)twos.size() > 1){
            ans[ones.back()][twos[0]] = 1;
            ans[twos[0]][ones.back()] = 1;
            ans[twos.back()][ones.back()] = 1;
            ans[ones.back()][twos.back()] = 1;
        }
    }
//    for(int i = 0;i < n;++i){
//        for(int j = i + 1;j < n;++j){
//            if(ans[i][j])cout << i << ", " << j << '\n';
//        }
//    }
    build(ans);
    return 1;
}


#endif // SUPERTREES_H_INCLUDED

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:50:17: warning: unused variable 'node' [-Wunused-variable]
   50 |             int node = dsu1.FindRep(j);
      |                 ^~~~
supertrees.cpp:63:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |         for(int j = 1;j < ones.size();++j){
      |                       ~~^~~~~~~~~~~~~
supertrees.cpp:67:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |         for(int j = 1;j < twos.size();++j){
      |                       ~~^~~~~~~~~~~~~

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