Submission #550064

#	Time	Username	Problem	Language	Result	Execution time	Memory
550064		esomer	Connecting Supertrees (IOI20_supertrees)	C++17	21 / 100	198 ms	24108 KiB

supertrees

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

using namespace std;

struct DSU{
  vector<int> v;
  void init(int n){
    v.assign(n, -1);
  }
  int get(int x){return v[x] < 0 ? x : v[x] = get(v[x]);}

  void unite(int x, int y){
    x = get(x); y = get(y);
    if(x == y) return;
    if(x > y) swap(x, y);
    v[x] += v[y]; v[y] = x;
    return; 
  }

  bool check(vector<vector<int>>& p, vector<vector<int>>& ans){
    for(int i = 0; i < p.size(); i++){
      for(int j = 0; j < p.size(); j++){
        if(p[i][j] == 1){
          if(get(i) != get(j)) return 0;
        }else{
          if(get(i) == get(j)) return 0;
        }
      }
    }
    for(int i = 0; i < v.size(); i++){
      if(v[i] < 0){
        int lst = i;
        for(int j = 0; j < v.size(); j++){
          if(j == i) continue;
          if(v[j] == i){
            ans[j][lst] = ans[lst][j] = 1;
            lst = j;
          }
        }
      }
    }
    return 1;
  }
};

DSU UF;

void DFS(int x, vector<vector<int>>& adj, int r, vector<bool>& vis){
  UF.unite(r, x);
  if(vis[x]) return;
  vis[x] = 1;
  for(int i = 0; i < adj.size(); i++){
    if(i == x || adj[i][x] == 0) continue;
    DFS(i, adj, r, vis);
  }
}

int construct(vector<vector<int>> p) {
	int n = p.size();
	vector<bool> vis(n, 0);
	bool pos = 1;
  UF.init(n);
	vector<vector<int>> ans(n, vector<int>(n, 0));
  for(int i = 0; i < n; i++){
    if(!vis[i]){
      DFS(i, p, i, vis);
    }
  }
  if(UF.check(p, ans)){
    build(ans);
    return 1;
  }else return 0;
}

Compilation message (stderr)

supertrees.cpp: In member function 'bool DSU::check(std::vector<std::vector<int> >&, std::vector<std::vector<int> >&)':
supertrees.cpp:22:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |     for(int i = 0; i < p.size(); i++){
      |                    ~~^~~~~~~~~~
supertrees.cpp:23:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |       for(int j = 0; j < p.size(); j++){
      |                      ~~^~~~~~~~~~
supertrees.cpp:31:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for(int i = 0; i < v.size(); i++){
      |                    ~~^~~~~~~~~~
supertrees.cpp:34:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |         for(int j = 0; j < v.size(); j++){
      |                        ~~^~~~~~~~~~
supertrees.cpp: In function 'void DFS(int, std::vector<std::vector<int> >&, int, std::vector<bool>&)':
supertrees.cpp:53:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |   for(int i = 0; i < adj.size(); i++){
      |                  ~~^~~~~~~~~~~~
supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:62:7: warning: unused variable 'pos' [-Wunused-variable]
   62 |  bool pos = 1;
      |       ^~~

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