Submission #977679

#	Time	Username	Problem	Language	Result	Execution time	Memory
977679		SmuggingSpun	Connecting Supertrees (IOI20_supertrees)	C++14	21 / 100	176 ms	18260 KiB

supertrees

#include "supertrees.h"
#include<bits/stdc++.h>
using namespace std;
int construct(vector<vector<int>>p){
	int n = p.size();
	bool is_sub1 = true, is_sub2 = true;
	for(int i = 0; i < n; i++){
		for(int j = 0; j < n; j++){
			if(p[i][j] != 1){
				is_sub1 = false;
				i = n;
				break;
			}
			if(p[i][j] > 1){
				is_sub2 = false;
				i = n;
				break;
			}
		}
	}
	if(is_sub1){
		p = vector<vector<int>>(n, vector<int>(n, 0));
		for(int i = 1; i < n; i++){
			p[i][i - 1] = p[i - 1][i] = 1;
		}
		build(p);
		return 1;
	}
	if(is_sub2){
		vector<int>par(n);
		iota(par.begin(), par.end(), 0);
		function<int(int)>find_set;
		find_set = [&] (int n){
			return n == par[n] ? n : par[n] = find_set(par[n]);	
		};
		function<void(int, int)>merge = [&] (int a, int b){
			par[find_set(a)] = find_set(b);
		};
		vector<bool>vis(n, false);
		vector<vector<int>>edge(n);
		for(int i = 0; i < n; i++){
			if(vis[i]){
				for(int j = 0; j < n; j++){
					if(i != j && int(find_set(i) == find_set(j)) != p[i][j]){
						return 0;
					}
				}
				continue;
			}
			for(int j = 0; j < n; j++){
				if(i != j && p[i][j] == 0 && find_set(i) == find_set(j)){
					return 0;
				}
				if(p[i][j] == 1){
					merge(i, j);
					vis[j] = true;
				}
			}
		}
		for(int i = 0; i < n; i++){
			edge[find_set(i)].emplace_back(i);
		}
		p = vector<vector<int>>(n, vector<int>(n, 0));
		for(int i = 0; i < n; i++){
			for(int j = 1; j < edge[i].size(); j++){
				p[edge[i][j]][edge[i][j - 1]] = p[edge[i][j - 1]][edge[i][j]] = 1;
			}
		}
		build(p);
		return 1;
	}
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:65:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |    for(int j = 1; j < edge[i].size(); j++){
      |                   ~~^~~~~~~~~~~~~~~~
supertrees.cpp:72:1: warning: control reaches end of non-void function [-Wreturn-type]
   72 | }
      | ^

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