added required changes to vertical order traversal

Author: GunjanMA

Tree/Traverals/CPP/vertical order traversal.cpp

@@ -4,8 +4,12 @@
 /*---video tutorial of approach used---*/
 // link: https://www.youtube.com/watch?v=4w2Ri4VhgZo&list=PLjhq5EHRYAeLdh0xtn2v7wbQsVc8WAB2e&index=6&ab_channel=CodeCampaign
 
+#include<bits/stdc++.h>
+#include<sstream>
+using namespace std;
+
 /*----STRUCTURE OF TREE NODE-----*/
-/*
+
 class TreeNode{
     public:
     int val;
@@ -18,7 +22,56 @@ class TreeNode{
         this->right=NULL;
     }
 };
-*/
+
+
+// Function to Build Tree 
+
+TreeNode* Buildtree()
+{
+    int a;
+    cin >> a;
+    TreeNode *root = new TreeNode(a);
+    queue<TreeNode*> q;
+    q.push(root);
+    while (!q.empty())
+    {
+        cin >> a;
+        if (a != -1)
+        {
+            TreeNode *temp = new TreeNode(a);
+            if (q.front()->left == NULL){
+                q.front()->left = temp;
+            }
+            else
+            {
+                q.front()->right = temp;
+                q.pop();
+            }
+            q.push(temp);
+        }
+        else
+        {
+            if (q.front()->left == NULL)
+            {
+                cin >> a;
+                if (a == -1){
+                    q.pop();
+                }
+                else{
+                    TreeNode *temp1 = new TreeNode(a);
+                    q.front()->right = temp1;
+                    q.pop();
+                    q.push(temp1);
+                }
+            }
+            else{
+                q.pop();
+            }
+        }
+    }
+    return root;
+}
+
 
 /*-------- FUNCTION FOR VERTICAL ORDER TRAVERSAL---------*/
 
@@ -31,6 +84,8 @@ void PrintVerticalOrder(TreeNode* root, int d, map<int, vector<int> > &m){
     PrintVerticalOrder(root->right,d+1,m);
 }
 
+// Driver Code
+
 int main(){
 	// fast I/O
     ios_base::sync_with_stdio(false);
@@ -53,4 +108,23 @@ int main(){
 
 
     return 0;
-}
+}
+
+/*---- SAMPLE INPUT/OUTPUT FOR A TREE ----*/
+/*
+input : 1 2 3 4 5 6  -1 -1 -1 -1 -1 -1 -1
+tree corresponding to the input: 
+
+             1
+          /      \
+       2           3
+    /     \       /
+   4       5     6
+
+output:
+4
+2
+1 5 6
+3
+this is the vertical order traversal of a tree
+*/