This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "supertrees.h"
#include <bits/stdc++.h>
using namespace std;
const int maxn=1010;
queue<int> q,q2;
bool vis[maxn];
int fa[maxn],line[maxn];
int construct(vector<vector<int> > p) {
	int n = p.size();
	vector<vector<int> > ans;
	for (int i = 0; i < n; i++) {
		vector<int> row;
		row.resize(n);
		ans.push_back(row);
	}
	for (int i=0;i<n;i++) for (int j=0;j<n;j++) if (p[i][j]==3) return 0;
	int lst;
	for (int i=0;i<n;i++) if (!vis[i]) {
		q.push(i);
		vector<int> circle; circle.clear();
		while (!q.empty()) {
			int u=q.front(); q.pop();
			if (vis[u]) continue;
			circle.push_back(u);
			q2.push(u); lst=-1;
			while (!q2.empty()) {
				int v=q2.front(); q2.pop();
				if (vis[v]) continue;
				vis[v]=1;
				//printf("%d %d %d\n",i,u,v);
				fa[v]=i,line[v]=u;
				if (lst>-1) ans[lst][v]=ans[v][lst]=1;
				lst=v;
				for (int j=0;j<n;j++) {
					if (p[v][j]==2) q.push(j);
					else if (p[v][j]==1) q2.push(j);
				}
			}
		}
		if (circle.size()<=1) continue;
		if (circle.size()==2) return 0;
		circle.push_back(circle[0]);
		for (int j=0;j<circle.size()-1;j++) ans[circle[j]][circle[j+1]]=ans[circle[j+1]][circle[j]]=1;
	}
	//printf("OK\n");
	for (int i=0;i<n;i++)
	for (int j=0;j<n;j++) {
		if (p[i][j]==0) {
			if (fa[i]==fa[j]) {
				//printf("??\n");
				return 0;
			}
		}
		if (p[i][j]==1) {
			if (line[i]!=line[j]) {
				//printf("%d %d %d %d %d %d\n",i,j,fa[i],fa[j],line[i],line[j]);
				//printf("??\n");
				return 0;
			}
		}
		if (p[i][j]==2) {
			if (fa[i]!=fa[j]||line[i]==line[j]) {
				//printf("??\n");
				return 0;
			}
		}
	}
	build(ans);
	return 1;
}
Compilation message (stderr)
supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:43:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |   for (int j=0;j<circle.size()-1;j++) ans[circle[j]][circle[j+1]]=ans[circle[j+1]][circle[j]]=1;
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