Binary Tree Node Structure in DSA Go - Execution Trace

Concept Flow - Binary Tree Node Structure

Create new node

↓

Assign data value

↓

Set left child pointer to nil

↓

Set right child pointer to nil

↓

Node ready for linking in tree

This flow shows how a binary tree node is created with data and two child pointers initialized to nil.

Execution Sample

DSA Go

type Node struct {
    data  int
    left  *Node
    right *Node
}

root := &Node{data: 10, left: nil, right: nil}

This code defines a binary tree node structure and creates a root node with data 10 and no children.

Execution Table

Step	Operation	Node Created	Left Pointer	Right Pointer	Visual State
1	Create new node	Node(data=10)	undefined	undefined	┌────────┐ │ data:10│ │ left:∅ │ │right:∅ │ └────────┘
2	Assign data value	Node(data=10)	undefined	undefined	┌────────┐ │ data:10│ │ left:∅ │ │right:∅ │ └────────┘
3	Set left pointer to nil	Node(data=10)	nil	undefined	┌────────┐ │ data:10│ │ left:∅ │ │right:∅ │ └────────┘
4	Set right pointer to nil	Node(data=10)	nil	nil	┌────────┐ │ data:10│ │ left:∅ │ │right:∅ │ └────────┘
5	Node ready for linking	Node(data=10)	nil	nil	┌────────┐ │ data:10│ │ left:∅ │ │right:∅ │ └────────┘

💡 All pointers initialized to nil, node is ready to be linked in the tree.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
node.data	undefined	10	10	10	10	10
node.left	undefined	undefined	undefined	nil	nil	nil
node.right	undefined	undefined	undefined	undefined	nil	nil

Key Moments - 2 Insights

Why are left and right pointers set to nil initially?

Because in the execution_table rows 3 and 4, we see left and right pointers assigned nil to indicate no children yet, preventing accidental references.

Is the data value assigned before or after pointers are set?

Data is assigned first as shown in step 2, then pointers are set to nil in steps 3 and 4, ensuring the node has valid data before linking.

Visual Quiz - 3 Questions

Look at the execution_table at step 1, what is the state of the left pointer?

A nil

B points to another node

C undefined

D points to itself

💡 Hint

Check the 'Left Pointer' column at step 1 in execution_table.

At which step do both left and right pointers become nil?

A Step 2

B Step 4

C Step 3

D Step 5

💡 Hint

Look at the 'Left Pointer' and 'Right Pointer' columns in execution_table rows.

If we skip setting right pointer to nil, what would be the final state of node.right?

A undefined or garbage value

B nil

C points to left child

D points to data

💡 Hint

Refer to variable_tracker for node.right initialization and step 4 in execution_table.

Concept Snapshot

Binary Tree Node Structure:
- Each node holds data and two pointers: left and right.
- Pointers start as nil (no children).
- Nodes link by assigning these pointers.
- This structure forms the basis for binary trees.

Full Transcript

This visual trace shows how a binary tree node is created in Go. First, a new node is made with data 10. Then, its left and right pointers are set to nil, meaning no children yet. The node is now ready to be linked into a binary tree. The execution table tracks each step and the node's state. The variable tracker shows data and pointers before and after each step. Key moments clarify why pointers start as nil and the order of assignments. The quiz tests understanding of pointer initialization and node state.