Segmentation Fault

#1
#2

Ambuj,… There are few errors in your code… Firstly your code is not producing any sort of output… So Firstly I would suggest you to change the buildtree function firstly… as it is given in the question that you need to build the tree using queue… So use the approach as :

node* build_tree()
{
int data;
queue<node*> q;
cin>>data;
node* root=new node(data);
q.push(root);
int c1,c2;

while(!q.empty())
{
    node *f=q.front();
    q.pop();
    cin>>c1>>c2;
    if(c1!=-1)
    {
        f->left=new node(c1);
        q.push(f->left);
    }
    if(c2!=-1)
    {
        f->right=new node(c2);
        q.push(f->right);
    }
}
return root;

}

#3

I applied this buildtree() function in my code but the code is not producing any output. Could you please help me with this.

#4

Pls share the edited code… With this buildtree function so that I could make changes in your code…

#5

Hello @yuktimutreja01
Please refer for the edited code: -

#6

Ambuj, the approach you are trying to use is not correct… You need to use the approach of horizontal distance in your code to print the top view as,
void topview(node *root)
{
if(root==NULL)
{
return;
}
queue<node *>q;
map<int,int> m;
int hd=0;
root->hd=hd;
q.push(root);
while(q.size())
{
hd=root->hd;
if(m.count(hd)==0)
{
m[hd]=root->data;
}
if(root->left)
{
root->left->hd=hd-1;
q.push(root->left);
}
if(root->right)
{
root->right->hd=hd+1;
q.push(root->right);
}
q.pop();
root=q.front();
}
for(auto i=m.begin(); i!=m.end();i++)
{
cout<second<<" ";
}
}

This approach is well explained in the tutorial link as : https://youtu.be/LtO96Ici8kc