Submission #812706

#	Time	Username	Problem	Language	Result	Execution time	Memory
812706		KemalK	Connecting Supertrees (IOI20_supertrees)	C++17	40 / 100	172 ms	24012 KiB

supertrees

#include "supertrees.h"
#include <vector>
#include <bits/stdc++.h>
using namespace std;
const int N = 1e3 + 5;
int pr[N];
int sz[N];
int get(int x){
	if (pr[x] == x){
		return x;
	}
	return (pr[x] = get(pr[x]));
}
void unit(int a, int b){
	a = get(a);
	b = get(b);
	if (a != b){
		if (sz[a] < sz[b]){
			swap(a, b);
		}
		pr[b] = a;
		sz[a] += sz[b];
	}
}
int construct(std::vector<std::vector<int>> p) {
	int n = p.size();
	for (int i = 0; i < n; i++){
		pr[i] = i; sz[i] = 1;
	}
	int check = 0;
	for (int i = 0; i < n; i++){
		for (int j = 0; j < n; j++){
			if (p[i][j]){
				unit(i, j);
				check = max(check, p[i][j]);
			}
		}
	}
	for (int i = 0; i < n; i++){
		for (int j = 0; j < n; j++){
			if (p[i][j] == 0 and get(i) == get(j)){ //impossible
				return 0;
			}
		}
	}
	vector <vector<int>> answer(n, vector<int>(n));
	if(!check){
		build(answer);
		return 1;	
	}
	for (int i = 0; i < n; i++){
		vector <int> branch;
		for (int j = 0; j < n; j++){
			if (get(j) == i){
				branch.push_back(j);
			}
		}
		for (int j = 0; j + 1 < branch.size(); j++){
			answer[branch[j]][branch[j + 1]] = 1;
			answer[branch[j + 1]][branch[j]] = 1;
		}
		if (check == 2){
			if(branch.size() == 2){
				return 0;
			}
			if (branch.size() > 2){
				answer[branch[0]][branch.back()] = 1;
				answer[branch.back()][branch[0]] = 1;
			}
		}
	}
	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:58:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |   for (int j = 0; j + 1 < branch.size(); 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