Tree top view

c++/Tree_top_view.cpp

@@ -0,0 +1,77 @@
+#include<bits/stdc++.h>
+
+using namespace std;
+
+class Node {
+    public:
+        int data;
+        Node *left;
+        Node *right;
+        Node(int d) {
+            data = d;
+            left = NULL;
+            right = NULL;
+        }
+};
+
+class Solution {
+    public:
+  		Node* insert(Node* root, int data) {
+            if(root == NULL) {
+                return new Node(data);
+            } else {
+                Node* cur;
+                if(data <= root->data) {
+                    cur = insert(root->left, data);
+                    root->left = cur;
+                } else {
+                    cur = insert(root->right, data);
+                    root->right = cur;
+               }
+
+               return root;
+           }
+        }
+/*
+class Node {
+    public:
+        int data;
+        Node *left;
+        Node *right;
+        Node(int d) {
+            data = d;
+            left = NULL;
+            right = NULL;
+        }
+};
+
+*/
+
+    void topView(Node * root) {
+        queue<pair<Node*, int>> q;
+        map<int, int> m;
+        q.push(make_pair(root, 0));
+        while(!q.empty()){
+            Node* u = q.front().first;
+            int v = q.front().second;
+            q.pop();
+            if(u->left){
+                q.push(make_pair(u->left, v-1));
+                if(!m.count(v-1)){
+                    m[v-1] = u->left->data;
+                }
+            }
+            if(u->right){
+                q.push(make_pair(u->right, v+1));
+                if(!m.count(v+1)){
+                    m[v+1] = u->right->data;
+                }
+            }
+        }
+        for(auto x:m){
+            cout<<x.second<<" ";
+        }
+        cout<<endl;
+    }
+
+}; //End of Solution