Submission #550138

#	Time	Username	Problem	Language	Result	Execution time	Memory
550138		esomer	Connecting Supertrees (IOI20_supertrees)	C++17	40 / 100	253 ms	23500 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 k = 0; k < v.size(); k++){
      if(v[k] < 0){
        vector<int> c;
        c.push_back(k);
        for(int j = 0; j < v.size(); j++){
          if(v[j] == k) c.push_back(j);
        }
        bool global_pos = 0;
        for(int i : c){
          if(global_pos) break;
          bool pos = 1;
          vector<int> three;
          vector<int> two;
          vector<int> one;
          for(int j : c){
            if(j == i) continue;
            if(p[i][j] == 3) three.push_back(j);
            else if(p[i][j] == 2) two.push_back(j);
            else if(p[i][j] == 1) one.push_back(j);
            else pos = 0;
          }
          if((three.size() > 0 && three.size() < 3) || (two.size() > 0 && two.size() < 2) || (two.size() > 0 && three.size() > 0)){
            pos = 0;
          }
          for(int q : three){
            for(int j : three){
              if(q == j) continue;
              if(p[q][j] != 3){
                pos = 0;
              }
            }
            for(int j : one){
              if(p[q][j] != 3){
                pos = 0;
              }
            }
          }
          for(int q : two){
            for(int j : two){
              if(q == j) continue;
              if(p[q][j] != 2){
                pos = 0;
              }
            }
            for(int j : one){
              if(p[q][j] != 2){
                pos = 0;
              }
            }
          }
          for(int q : one){
            for(int j : one){
              if(q == j) continue;
              if(p[q][j] != 1){
                pos = 0;
              }
            }
          }
          if(pos){
            global_pos = 1;
            if(three.size() > 0){
              ans[i][three[three.size() - 1]] = ans[i][three[three.size() - 2]] = 1;
              ans[three[three.size() - 1]][i] = ans[three[three.size() - 2]][i] = 1;
              ans[three[0]][i] = ans[i][three[0]] = 1;
              for(int j = 0; j < three.size() - 1; j++){
                ans[three[j]][three[j+1]] = ans[three[j+1]][three[j]] = 1;
              }
            }
            if(two.size() > 0){
              ans[i][two[two.size() - 1]] = ans[two[two.size() - 1]][i] = 1;
              ans[i][two[0]] = ans[two[0]][i] = 1;
              for(int j = 0; j < two.size() - 1; j++){
                ans[two[j]][two[j+1]] = ans[two[j+1]][two[j]] = 1;
              }
            }
            if(one.size() > 0){
              ans[one[0]][i] = ans[i][one[0]] = 1;
              for(int j = 0; j < one.size() - 1; j++){
                ans[one[j]][one[j+1]] = ans[one[j+1]][one[j]] = 1;
              }
            }
          }
        }
        if(!global_pos) return 0;
      }
    }
    return 1;
  }
};
 
DSU UF2;
 
int construct(vector<vector<int>> p) { //
	int n = p.size();
	vector<bool> vis(n, 0);
	UF2.init(n);
	vector<vector<int>> ans(n, vector<int>(n, 0));
	for(int i = 0; i < n; i++){
		if(!vis[i]){
			vis[i] = 1;
			for(int j = 0; j < n; j++){
				if(i == j || p[i][j] == 0) continue;
				if(vis[j] == 1) return 0;
				vis[j] = 1;
				UF2.unite(i, j);
			}
		}else{
			for(int j = 0; j < n; j++){
				if((p[i][j] != 0 && vis[j] == false) || (p[i][j] != 0 && vis[j] == 1 && UF2.get(i) != UF2.get(j))){
					return 0;
				}
			}
		}
	}
	if(UF2.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:21:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |     for(int k = 0; k < v.size(); k++){
      |                    ~~^~~~~~~~~~
supertrees.cpp:25:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |         for(int j = 0; j < v.size(); j++){
      |                        ~~^~~~~~~~~~
supertrees.cpp:85:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |               for(int j = 0; j < three.size() - 1; j++){
      |                              ~~^~~~~~~~~~~~~~~~~~
supertrees.cpp:92:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |               for(int j = 0; j < two.size() - 1; j++){
      |                              ~~^~~~~~~~~~~~~~~~
supertrees.cpp:98:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   98 |               for(int j = 0; j < one.size() - 1; j++){
      |                              ~~^~~~~~~~~~~~~~~~

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