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  1. Prepare
  2. Data Structures
  3. Trees
  4. Tree : Top View
  5. Discussions

Tree : Top View

  • parmarabhishek_1
     + 6 comments

    This is the actual code for top view of a tree :

    typedef pair<int,int> v_h; 
map <int,v_h> m; // map
map <int, v_h> :: iterator itr; //itterator

void store_view(node * root,int i,int h)
    {
    if(root==NULL)
        return;
    itr=m.find(i);
    if(itr==m.end())
        m[i]=make_pair(h,root->data);
    else
    {
        if(itr->second.first > h)
            m[i]=make_pair(h,root->data);
    }
    if(root->left!=NULL)
        store_view(root->left,i-1,h+1);
    if(root->right!=NULL)
        store_view(root->right,i+1,h+1);
     
}

void print_map()
    {
    for(itr = m.begin(); itr != m.end(); ++itr)
        cout<<itr->second.second<<" ";
}

void topView(node * root)
{
   store_view(root,0,0);
   print_map();
    return;
}

    but the problem demands the top view according to the root node only :

    void for_left(node * root)
{
    if(root->left!=NULL)
        for_left(root->left);
    cout<<root->data<<" ";
}


void for_right(node * root)
{
    cout<<root->data<<" ";
    if(root->right!=NULL)
        for_right(root->right);
}

void topView(node * root)
{
    if(root->left!=NULL)
        for_left(root->left);
    cout<<root->data<<" ";
    if(root->right!=NULL)
        for_right(root->right);
    
}