Vertical Order Traversal of Binary Tree in DSA Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Vertical Order Traversal of a Binary Tree?

It is a way to print the nodes of a binary tree column by column from left to right. Nodes in the same vertical line are grouped together.

beginner

How do we assign horizontal distances (HD) to nodes in Vertical Order Traversal?

The root node is assigned HD = 0. For any node, its left child has HD = parent's HD - 1, and its right child has HD = parent's HD + 1.

intermediate

Why do we use a queue and a map in Vertical Order Traversal?

A queue helps in level order traversal to process nodes level by level. A map stores nodes grouped by their horizontal distance for final vertical order output.

intermediate

What data structure is commonly used to keep track of nodes and their horizontal distances during traversal?

A queue of pairs (node, horizontal distance) is used to process nodes in order and track their vertical positions.

advanced

How do we handle nodes that share the same horizontal distance and level in Vertical Order Traversal?

They are printed in the order they appear in the level order traversal, usually from left to right.

In Vertical Order Traversal, what horizontal distance is assigned to the root node?

A 1

B -1

C 0

D Depends on tree height

The root node is always assigned horizontal distance 0.

Which data structure is best to store nodes grouped by their horizontal distance?

A Map or Dictionary

B Array

C Stack

D Linked List

A map or dictionary stores nodes by their horizontal distance keys.

What traversal method is combined with horizontal distance tracking for Vertical Order Traversal?

A Postorder

B Inorder

C Preorder

D Level order (BFS)

Level order traversal (BFS) is used to process nodes level by level.

If a node is at horizontal distance 2, where is it located relative to the root?

A Two steps right

B Two steps left

C At root

D Cannot determine

Positive horizontal distance means right side of the root.

How do we print the final vertical order after traversal?

A From highest to lowest horizontal distance

B From lowest to highest horizontal distance

C Random order

D Only nodes at horizontal distance 0

We print nodes from the smallest to largest horizontal distance (left to right).

Explain step-by-step how to perform Vertical Order Traversal on a binary tree.

Think about how to combine level order traversal with horizontal distance tracking.

Describe how horizontal distances change when moving to left and right children in a binary tree.

Consider the root as the center point.