Create top_view1

top_view1

@@ -0,0 +1,35 @@
+class Solution
+{
+    public:
+    //Function to return a list of nodes visible from the top view 
+    //from left to right in Binary Tree.
+    vector<int> topView(Node *root)
+    {
+        vector<int> ans; 
+        if(root == NULL) return ans; 
+        map<int,int> mpp; 
+        queue<pair<Node*, int>> q; 
+        q.push({root, 0}); 
+        while(!q.empty()) {
+            auto it = q.front(); 
+            q.pop(); 
+            Node* node = it.first; 
+            int line = it.second; 
+            if(mpp.find(line) == mpp.end()) mpp[line] = node->data; 
+
+            if(node->left != NULL) {
+                q.push({node->left, line-1}); 
+            }
+            if(node->right != NULL) {
+                q.push({node->right, line + 1}); 
+            }
+
+        }
+
+        for(auto it : mpp) {
+            ans.push_back(it.second); 
+        }
+        return ans; 
+    }
+
+};