Submission #591813

#	Time	Username	Problem	Language	Result	Execution time	Memory
591813		penguinhacker	Connecting Supertrees (IOI20_supertrees)	C++17	0 / 100	1 ms	328 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
using namespace std;

const int mxN=1000;
int n, who[mxN], cnt;
vector<int> adj[mxN], cur_component;
vector<vector<int>> p, cmp, ans, edge2;
bool vis[mxN];

void dfs0(int i) {
	who[i]=cnt;
	for (int j=0; j<n; ++j)
		if (i!=j&&who[j]==-1&&p[i][j])
			dfs0(j);
}

bool check0() {
	memset(who, -1, 4*n);
	cnt=0;
	for (int i=0; i<n; ++i)
		if (who[i]==-1)
			dfs0(i), ++cnt;
	for (int i=0; i<n; ++i)
		for (int j=i+1; j<n; ++j)
			if (who[i]==who[j]&&p[i][j]==0)
				return 0;
	return 1;
}

void dfs1(int i) {
	who[i]=cnt;
	for (int j=0; j<n; ++j)
		if (i!=j&&who[j]==-1&&p[i][j]==1)
			dfs1(j);
}

bool check1() {
	memset(who, -1, 4*n);
	for (int i=0; i<n; ++i)
		if (who[i]==-1)
			cnt=i, dfs1(i);
	for (int i=0; i<n; ++i)
		for (int j=i+1; j<n; ++j)
			if (who[i]==who[j]&&p[i][j]!=1)
				return 0;
	for (int j=0; j<cnt; ++j) {
		int last=-1;
		for (int i=0; i<n; ++i)
			if (who[i]==j) {
				if (last!=-1)
					ans[last][i]=ans[i][last]=1;
				last=i;
			}
	}
	return 1;
}

void dfs2(int i) {
	vis[i]=1;
	cur_component.push_back(i);
	for (int j=0; j<n; ++j)
		if (who[j]==j&&!vis[j]&&i!=j&&p[i][j]==2)
			dfs2(j);
}

bool check2() {
	memset(vis, 0, n);
	for (int i=0; i<n; ++i) {
		if (i!=who[i]||vis[i])
			continue;
		cur_component.clear();
		dfs2(i);
		if (cur_component.size()<=2)
			return 0;
		for (int j=0; j<cur_component.size(); ++j) {
			int a=cur_component[j], b=cur_component[(j+1)%cur_component.size()];
			ans[a][b]=ans[b][a]=1;
		}
	}
	return 1;
}

int construct(vector<vector<int>> _p) {
	p=_p, n=p.size();
	for (int i=0; i<n; ++i)
		for (int j=i+1; j<n; ++j)
			if (p[i][j]==3)
				return 0;
	ans=edge2=vector<vector<int>>(n, vector<int>(n));
	if (!check0()||!check1()||!check2())
		return 0;
	build(ans);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'bool check2()':
supertrees.cpp:76:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |   for (int j=0; j<cur_component.size(); ++j) {
      |                 ~^~~~~~~~~~~~~~~~~~~~~

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