You are given a pointer to the root of a binary tree. Print the top view of the binary tree. Top view means when you look the tree from the top the nodes, what you will see will be called the top view of the tree. See the example below.

Example: gfg top view of tree

/* This is not the entire code. It's just the function which implements 
   bottom view. You need to write required code. */

// Obj class is used to store node with it's distance from parent.
class Obj
{
    public:
        Node *root;
        int dis; // distance from parent node. distance of root node will be 0.

        Obj(Node *node, int dist)
        {
            root = node;
            dis = dist;
        }
};

void topView(Node *root)
{
    queue<Obj*> q;
    q.push(new Obj(root, 0));
    map<int,int> m;

    while(!q.empty())
    {
        Obj *ob = q.front();
        q.pop();
		
      	/* insert node of unique distance from parent node. ignore repitation 
           of distance. */
        if(m.find(ob->dis) == m.end())
            m[ob->dis] = ob->root->data;

        if(ob->root->left != NULL)
            q.push(new Obj(ob->root->left, ob->dis-1)); 
        if(ob->root->right != NULL)
            q.push(new Obj(ob->root->right, ob->dis+1));
    }

  	// printing nodes.
    for(auto it=m.begin(); it!=m.end(); it++)
        cout << it->second << "\t";

    cout << endl;
}