Submission #416432

#	Time	Username	Problem	Language	Result	Execution time	Memory
416432		ioi	Connecting Supertrees (IOI20_supertrees)	C++14	19 / 100	368 ms	24116 KiB

supertrees

#include "supertrees.h"
#include <vector>
#include<bits/stdc++.h>
using namespace std ;
const int N = 1002;
int dsu[N] , sz[N];

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

    return dsu[u] = get(dsu[u]);



}

void connect(int u , int v){


    u = get(u) , v = get(v);
    if(u == v)return ;

    if(sz[u] > sz[v])swap(u , v);

    sz[v] += sz[u];

    dsu[u] = v ;



}

bool same(int u , int v){
    u = get(u) , v = get(v);

    return u == v ;

}
int construct(vector<vector<int>> p) {
	int n = p.size();
	vector<vector<int>> answer (n , vector<int> (n , 0));
    for(int i = 0 ; i < n ; i ++)sz[i] = 1 , dsu[i] = i ;

    for(int i = 0 ; i < n ; i ++){
        for(int j = 0 ; j < n ; j ++){
            if(p[i][j])connect(i , j);

        }
    }
    map<int, set<int> > mp ;


    for(int i = 0 ; i < n ; i ++){
        for(int j = 0 ; j < n ;j ++)
        {
            if(p[i][j] == 0&& same(i , j) || (p[i][j] && sz[get(dsu[i])] == 2))return 0 ;
             if(p[i][j] && i != j)mp[dsu[i]].insert(i) , mp[dsu[i]].insert(j);

        }
    }
    for(auto f : mp){
        int past = *(f.second.begin());
        auto p = f.second .begin();
        p ++ ;

        for(int i = 1 ; i < f.second.size() ; i ++){

            int curr = *p;

            p ++;
            answer[past][curr] = answer[curr][past] = 1 ;
            past = curr ;
        }
        p -- ;
        past = *f.second.begin();
        answer[past][*p] = answer[*p][past] = 1 ;


    }



	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:57:28: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   57 |             if(p[i][j] == 0&& same(i , j) || (p[i][j] && sz[get(dsu[i])] == 2))return 0 ;
supertrees.cpp:67:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::set<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |         for(int i = 1 ; i < f.second.size() ; i ++){
      |                         ~~^~~~~~~~~~~~~~~~~

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