Submission #366766

#	Time	Username	Problem	Language	Result	Execution time	Memory
366766		SlavicG	Connecting Supertrees (IOI20_supertrees)	C++17	40 / 100	295 ms	26348 KiB

supertrees

#include "supertrees.h"
#include "bits/stdc++.h"
 
using namespace std;
 
#define              ll              long long
 
#define       forn(i,n)              for(int i=0;i<n;i++)
#define          all(v)              v.begin(), v.end()
#define         rall(v)              v.rbegin(),v.rend()
 
#define            pb                push_back
#define          sz(a)               (int)a.size()
#define         fastio               ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
 
const int N = 1001;
vector<int> adj[N];
bool vis[N];
set<int> n2;
bool two_cur;
vector<int> component;
 
int par[N];
int get(int a){
	while(par[a]!=a)a=par[a];
	return a;
}
void uni(int a,int b){
	a = get(a);
	b = get(b);
	if(a==b)return;
	par[b] = a;
}
void dfs(int u)
{
	vis[u] = true;
	if(n2.count(u))two_cur = true;
	component.pb(u);
	for(auto x : adj[u]){
		if(!vis[x])dfs(x);
	}
}
int construct(vector<vector<int>> p)
{
	int n = sz(p);
	vector<vector<int>> ans;
	ans.resize(n);
	for(int i=0;i < n;i++)
		par[i]=i;
	for(int i =0;i < n;i++)ans[i].resize(n);
	forn(i,n)forn(j,n)ans[i][j]=0;
	bool two = false;
	bool one = false;
	for(int i = 0;i < n;i++)
	{
		for(int j = 0;j < n;j++)
		{
			if(p[i][j]==2)two=true;
			if(p[i][j] == 1)one = true;
			if(p[i][j]){
				uni(i,j);
				adj[i].pb(j);
			}
		}
	}
	for(int i = 0;i < n;i++)
	{
		for(int j =0;j < n;j++)
		{
			if(get(i)==get(j) && !p[i][j])return 0;
		}
	}
	for(int i = 0;i < n;i++)
	{
		for(int j = 0;j < n;j++)
		{
			if(p[i][j] == 2)n2.insert(i);
		}
	}
	for(int i = 0;i < n;i++)
	{
		if(!vis[i]){
			component.clear();
			two_cur = false;
			dfs(i);
			if(sz(component) == 2 && two_cur)return 0;
			for(int j = 1;j < sz(component);j++)
			{
				ans[component[j]][component[j-1]] = ans[component[j-1]][component[j]] = 1; 
			}
			if(two_cur && sz(component) > 1)ans[component.back()][component[0]] = ans[component[0]][component.back()] = 1;
		}
	}
	build(ans);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:52:7: warning: variable 'two' set but not used [-Wunused-but-set-variable]
   52 |  bool two = false;
      |       ^~~
supertrees.cpp:53:7: warning: variable 'one' set but not used [-Wunused-but-set-variable]
   53 |  bool one = false;
      |       ^~~

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