#include<bits/stdc++.h>
using namespace std;
#define ll long long
struct DSU
{
int n;
vector<int>trace;
DSU(int _n=0)
{
n=_n;
trace.resize(n+7);
iota(trace.begin(),trace.end(),0);
}
int get(int x)
{
return trace[x]==x?trace[x]:trace[x]=get(trace[x]);
}
void connect(int x,int y)
{
int u=get(x);
int v=get(y);
if(u==v)return ;
trace[v]=u;
}
};
int construct(vector<vector<int> >p)
{
int n=p.size();
DSU only(n);
DSU can(n);
for(int i=0;i<=n-1;i++)
{
for(int j=0;j<=n-1;j++)if(p[i][j]==3)return 0;
}
vector<vector<int> >b(n,vector<int>(n,0));
for(int i=0;i<=n-1;i++)
{
for(int j=i+1;j<=n-1;j++)
{
if(p[i][j]==1)only.connect(i,j);
if(p[i][j])can.connect(i,j);
}
}
for(int i=0;i<=n-1;i++)
{
if(can.get(i)!=i)continue;
vector<int>q;
for(int node=0;node<=n-1;node++)
{
if(can.get(node)==i&&only.get(node)==node)q.push_back(node);
}
if((int)q.size()==1)continue;
if((int)q.size()==2)return 0;
for(int node=0;node<=q.size()-2;node++)
{
int node_x=q[node];
int node_y=q[(node+1)%n];
b[node_x][node_y]=1;
b[node_y][node_x]=1;
}
}
for(int i=0;i<=n-1;i++)if(only.get(i)!=i)
{
int node=only.get(i);
b[node][i]=b[i][node]=1;
}
for(int i=0;i<=n-1;i++)
{
for(int j=i+1;j<=n-1;j++)
{
if(only.get(i)==only.get(j))
{
if(p[i][j]!=1)return 0;
}
else if(can.get(i)==can.get(j))
{
if(p[i][j]!=2)return 0;
}
else
{
if(p[i][j])return 0;
}
}
}
build(b);
return 1;
}
Compilation message
supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:54:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
54 | for(int node=0;node<=q.size()-2;node++)
| ~~~~^~~~~~~~~~~~
supertrees.cpp:85:5: error: 'build' was not declared in this scope
85 | build(b);
| ^~~~~
