DSA

Tree Traversals

Master the different ways to visit every node in a tree: Depth-First Search and Breadth-First Search.

By TechCoder TeamLast updated: 2026-06-02
In a Nutshell

Master the different ways to visit every node in a tree: Depth-First Search and Breadth-First Search. This hands-on tutorial focuses on practical implementation of tree traversals concepts.

Tree Traversals

Traversing a tree means visiting every node once in a specific order. Unlike linear structures (arrays, linked lists), there are multiple logical ways to traverse a tree.

1. Depth-First Search (DFS)

DFS uses recursion (or a stack) to go as deep as possible before backtracking.

A. Preorder (Root, Left, Right)

Order: Visit Root -> Traverse Left Subtree -> Traverse Right Subtree.

B. Inorder (Left, Root, Right)

Order: Traverse Left Subtree -> Visit Root -> Traverse Right Subtree.

[!TIP] Inorder traversal of a BST always yields values in sorted order!

C. Postorder (Left, Right, Root)

Order: Traverse Left Subtree -> Traverse Right Subtree -> Visit Root.

2. Breadth-First Search (BFS)

Also known as Level Order Traversal. We visit all nodes at the current level before moving to the next.

3. Implementation in Python

PYTHON PLAYGROUND
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Quiz

Quiz

Question 1 of 2

Which traversal of a BST gives the elements in non-decreasing order?

Preorder
Inorder
Postorder
BFS