Submission #853684

#	Time	Username	Problem	Language	Result	Execution time	Memory
853684		ntkphong	Connecting Supertrees (IOI20_supertrees)	C++14	100 / 100	190 ms	22236 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
using namespace std;
 
vector<int> par;
 
int get_root(int u) {
    return par[u] == u ? u : par[u] = get_root(par[u]);
}
 
bool unite(int u, int v) {
    u = get_root(u);
    v = get_root(v);
 
    if(u == v) return false;
 
    par[v] = u;
    return true;
}
 
int construct(vector<vector<int>> p) {
	int n = p.size();
 
    par.resize(n);
    for(int i = 0; i < n; i ++) par[i] = i;
 
    vector<vector<int>> answer(n, vector<int> (n, 0));
    vector<bool> mark(n, false);
 
    for(int i = 0; i < n; i ++) {
        vector<int> a;
 
        for(int j = 0; j < n; j ++) {
            if(i == j || p[i][j] != 1) continue ;
            a.push_back(j);
        }
 
        if(a.empty()) continue ;
 
        for(int j = 0; j < a.size(); j ++) {
            if(unite(i, a[j])) {
                answer[i][a[j]] = 1;
                answer[a[j]][i] = 1;
            }
        }
    }
 
    for(int i = 0; i < n; i ++) {
        for(int j = 0; j < n; j ++) {
            if(i != j && p[i][j] == 1) {
                if(get_root(i) != get_root(j))
                    return 0;
            }
 
            if(i != j && p[i][j] == 0) {
                if(get_root(i) == get_root(j))
                    return 0;
            }
        }
    }
 
    for(int i = 0; i < n; i ++) {
        if(get_root(i) != i) continue ;
 
        vector<int> a;
 
        for(int j = 0; j < n; j ++) {
            if(i == j || p[i][j] != 2) continue ;
 
            if(mark[j]) return 0;
            a.push_back(j);
        }
 
        if(a.empty()) continue ;
 
        vector<int> b;
        b.push_back(i);
 
        for(int j = 0; j < a.size(); j ++) {
            if(unite(b.back(), a[j])) {
                answer[b.back()][a[j]] = 1;
                answer[a[j]][b.back()] = 1;
 
                b.push_back(a[j]);
            }
        }
 
        if(b.size() <= 2) return 0;
 
        answer[i][b.back()] = 1;
        answer[b.back()][i] = 1;
 
        for(int j = 0; j < n; j ++) {
            if(get_root(i) == get_root(j)) {
                mark[j] = true;
            }
        }
    }
 
    for(int i = 0; i < n; i ++) {
        for(int j = 0; j < n; j ++) {
            if(i != j && p[i][j] == 2) {
                if(get_root(i) != get_root(j) || mark[get_root(i)] == false)
                    return 0;
            }
 
            if(i != j && p[i][j] == 0) {
                if(get_root(i) == get_root(j))
                    return 0;
            }
        }
    }
    
    for(int i = 0; i < n; i ++) {
        for(int j = 0; j < n; j ++) {
            if(p[i][j] == 3) return 0;
        }
    }
 	
  	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:40:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |         for(int j = 0; j < a.size(); j ++) {
      |                        ~~^~~~~~~~~~
supertrees.cpp:79:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |         for(int j = 0; j < a.size(); j ++) {
      |                        ~~^~~~~~~~~~

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