Knowledge Guide
Home › DSA › Recursion

11 BST Inorder Traversal

Problem Statement

Write Recursive Approach for Inorder Traversal of Binary Tree.

Given a binary tree, write a recursive algorithm to perform an inorder traversal of the tree and return the elements in the order they were visited.

Examples

Example 1:

Input:
           5
         /   \
        3     8
       / \   / \
      2   4 7   9

Output:
Inorder Traversal: [2, 3, 4, 5, 7, 8, 9]

Explanation:
The binary tree has the following structure:
           5
         /   \
        3     8
       / \   / \
      2   4 7   9

Performing an inorder traversal visits the nodes in ascending order: 2, 3, 4, 5, 7, 8, 9.

Example 2:

Input:
           10
         /    \
        6      15
       / \    / \
      3   8  12  18
            \
             9

Output:
Inorder Traversal: [3, 6, 8, 9, 10, 12, 15, 18]

Explanation:
The binary tree has the following structure:
           10
         /    \
        6      15
       / \    / \
      3   8  12  18
            \
             9

Performing an inorder traversal visits the nodes in ascending order: 3, 6, 8, 9, 10, 12, 15, 18.

Example 3:

Input:
           20
         /    \
        12     25
       / \    / \
      8   15  22  28
     / \       \
    6   10      24

Output:
Inorder Traversal: [6, 8, 10, 12, 15, 20, 22, 24, 25, 28]

Explanation:
The binary tree has the following structure:
           20
         /    \
        12     25
       / \    / \
      8   15  22  28
     / \       \
    6   10      24

Performing an inorder traversal visits the nodes in ascending order: 6, 8, 10, 12, 15, 20, 22, 24, 25, 28.

Constraints:

Try it yourself

Try solving this question here:

🤖 Don't fully get this? Learn it with Claude

Stuck on 11 BST Inorder Traversal? Open Claude, copy a block below, and it'll teach you this exact concept — visually and interactively.

🎨 Explain it visually

Build the mental picture, not memorization.

I just read a lesson on **11 BST Inorder Traversal** (DSA) and want to truly understand it. Explain 11 BST Inorder Traversal from first principles using ONE vivid real-world analogy and a visual mental model — draw it as ASCII art or a clear step-by-step diagram — with a concrete example using real numbers. Then ask me one question to check I got the mental picture, and wait for my reply. If you're unsure or a claim isn't standard, say so and reason from first principles instead of guessing.
🤔 Walk me through it (interactive)

Socratic — adapts to where you're stuck.

Teach me **11 BST Inorder Traversal** interactively. Ask me ONE guiding question at a time, wait for my answer, and adapt to my confusion — build the idea with me step by step instead of explaining it all at once. If you're unsure or a claim isn't standard, say so and reason from first principles instead of guessing.
🧪 Quiz me & fix my gaps

Active recall exposes what you missed.

Quiz me on **11 BST Inorder Traversal** with 5 questions, easy to tricky, ONE at a time. Tell me if each answer is right; at the end, explain clearly what I got wrong and why. If you're unsure or a claim isn't standard, say so and reason from first principles instead of guessing.
🧠 Make it stick

Intuition + hook + flashcards for long-term memory.

Help me remember **11 BST Inorder Traversal** for the long term: give the one-sentence intuition, a memorable hook/mnemonic, a tiny worked example, and 3 active-recall flashcards (Q -> A). If you're unsure or a claim isn't standard, say so and reason from first principles instead of guessing.

📝 My notes

← 10 Inserting a new node in a BST12 Merge Sort →