Submission #731961

#	Time	Username	Problem	Language	Result	Execution time	Memory
731961		TheSahib	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	210 ms	24092 KiB

supertrees

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

using namespace std;

const int MAX = 1005;
int par[MAX];

int find_set(int v){
    if(par[v] < 0) return v;
    return par[v] = find_set(par[v]);
}

bool unite(int u, int v){
    u = find_set(u);
    v = find_set(v);
    if(u == v) return false;

    par[u] += par[v];
    par[v] = u;
    return true;
}

vector<int> g[MAX];
bool visited[MAX];
void dfs(int node, vector<int>& v){
    v[node] += 1;
    visited[node] = 1;
    for(int& to:g[node]){
        if(!visited[to]){
            dfs(to, v);
        }
    }
    visited[node] = 0;
}

int construct(vector<vector<int>> p) {
	int n = p.size();
    vector<vector<int>> ans(n, vector<int>(n));

    vector<bool> except(n, 0);
    for (int i = 0; i < n; i++)
    {
        for (int j = i + 1; j < n; j++)
        {
            if(p[i][j] == 1){
                except[i] = 1;
                ans[i][j] = 1;
                ans[j][i] = 1;
                break;
            }
        }
    }
    
    memset(par, -1, sizeof(par));
	for (int i = 0; i < n; i++)
    {
        if(except[i]) continue;
        for (int j = 0; j < n; j++)
        {
            if(except[j]) continue;
            if(p[i][j] == 2){
                unite(i, j);
            }
        }
    }
    vector<int> comps[MAX];
    for (int i = 0; i < n; i++)
    {
        if(except[i]) continue;
        comps[find_set(i)].push_back(i);
    }
    for(auto& v:comps){
        for (int i = 0; i < v.size(); i++)
        {
            if(i != 0){
                ans[v[i]][v[i - 1]] = 1;
            }
            if(i != v.size() - 1){
                ans[v[i]][v[i + 1]] = 1;
            }
        }
        if(v.size() > 2){
            ans[v.front()][v.back()] = 1;
            ans[v.back()][v.front()] = 1;
        }
    }
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            if(ans[i][j]){
                g[i].push_back(j);
            }
        }
    }
    
    for (int i = 0; i < n; i++)
    {
        vector<int> v(n, 0);
        dfs(i, v);
        if(v != p[i]) return 0;
    }
    
    
    build(ans);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:74:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |         for (int i = 0; i < v.size(); i++)
      |                         ~~^~~~~~~~~~
supertrees.cpp:79:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |             if(i != v.size() - 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