Submission #667248

#	Time	Username	Problem	Language	Result	Execution time	Memory
667248		YENGOYAN	Connecting Supertrees (IOI20_supertrees)	C++17	56 / 100	211 ms	26188 KiB

supertrees

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

using namespace std;

vector<int> par, sizes;

int get(int u){
    if(par[u] == u) return u;
    return par[u] = get(par[u]);
}

bool areInOne(int u, int v){
    return get(u) == get(v);
}

void union_sets(int u, int v){
    int a = get(u), b = get(v);
    if(a == b) return;
    if(sizes[a] < sizes[b]) swap(a, b);
    sizes[a] += sizes[b];
    par[b] = a;
}

vector<int> comp;

void dfs(int u, vector<vector<int>> &gp, vector<bool> &vis){
    comp.push_back(u);
    vis[u] = 1;
    for(int &v : gp[u]){
        if(!vis[v]){
            dfs(v, gp, vis);
        }
    }
}

int construct(vector<vector<int>> p) {

    int n = p.size();
    vector<vector<int>> gp(n, vector<int> (n));
    par = sizes = vector<int> (n);
    for(int i = 0; i < n; i++) par[i] = i, sizes[i] = 1;
    set<int> vec;
    for(int i = 0; i < n; i++){
        for(int j = i + 1; j < n; j++){
            if(!areInOne(i, j) && p[i][j] == 1){
                gp[i][j] = gp[j][i] = 1;
                union_sets(i, j);
            }
        }
    }
    vector<bool> used(n);
    for(int i = 0; i < n; i++){
        for(int j = i + 1; j < n; j++){
            if(p[i][j] == 1){
                used[i] = used[j] = 1;
                vec.insert(get(i));
            }
        }
    }
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            int u = get(i), v = get(j);
            if(u == v && !p[i][j]) return 0;
            if(u != v && p[i][j] == 1) return 0;
        }
    }
    vector<vector<int>> graph(n);
    for(int i = 0; i < n; i++){
        for(int j =  i + 1; j < n; j++){
            if(p[i][j]) {
                graph[i].push_back(j);
                graph[j].push_back(i);
            }
        }
    }
    vector<bool> vis(n);
    for(int i = 0; i < n; i++){
        if(vis[i]) continue;
        comp.clear();
        dfs(i, graph, vis);
        bool f = 0;
        vector<int> rightComp;
        int node = -1;
        for(int i = 0; i < comp.size(); i++){
            if(!used[comp[i]]) rightComp.push_back(comp[i]);
            else if(vec.find(comp[i]) != vec.end()) rightComp.push_back(comp[i]);
        }
        for(int i = 0; i < rightComp.size() - 1; i++){
            gp[rightComp[i]][rightComp[i + 1]] = gp[rightComp[i + 1]][rightComp[i]] = 1;
        }
        if(rightComp.size() > 2) gp[rightComp[0]][rightComp.back()] = gp[rightComp.back()][rightComp[0]] = 1;
        else if(rightComp.size() == 2){
            return 0;
        }
    }
    /*
        1 1 2 2 2
        1 1 2 2 2
        2 2 1 1 2
        2 2 1 1 2
        2 2 2 2 1




    */
    build(gp);
    return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:85:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |         for(int i = 0; i < comp.size(); i++){
      |                        ~~^~~~~~~~~~~~~
supertrees.cpp:89:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   89 |         for(int i = 0; i < rightComp.size() - 1; i++){
      |                        ~~^~~~~~~~~~~~~~~~~~~~~~
supertrees.cpp:82:14: warning: unused variable 'f' [-Wunused-variable]
   82 |         bool f = 0;
      |              ^
supertrees.cpp:84:13: warning: unused variable 'node' [-Wunused-variable]
   84 |         int node = -1;
      |             ^~~~

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