gfg top view of tree

1/* This is not the entire code. It's just the function which implements 
2   bottom view. You need to write required code. */
3
4// Obj class is used to store node with it's distance from parent.
5class Obj
6{
7    public:
8        Node *root;
9        int dis; // distance from parent node. distance of root node will be 0.
10
11        Obj(Node *node, int dist)
12        {
13            root = node;
14            dis = dist;
15        }
16};
17
18void topView(Node *root)
19{
20    queue<Obj*> q;
21    q.push(new Obj(root, 0));
22    map<int,int> m;
23
24    while(!q.empty())
25    {
26        Obj *ob = q.front();
27        q.pop();
28		
29      	/* insert node of unique distance from parent node. ignore repitation 
30           of distance. */
31        if(m.find(ob->dis) == m.end())
32            m[ob->dis] = ob->root->data;
33
34        if(ob->root->left != NULL)
35            q.push(new Obj(ob->root->left, ob->dis-1)); 
36        if(ob->root->right != NULL)
37            q.push(new Obj(ob->root->right, ob->dis+1));
38    }
39
40  	// printing nodes.
41    for(auto it=m.begin(); it!=m.end(); it++)
42        cout << it->second << "\t";
43
44    cout << endl;
45}