Linked List Traversal

Traversal

Linked List traversal involves visiting each node in the list exactly once, starting from the head and moving through the next pointers until the end is reached.

Traversal is essential for operations like searching, displaying, or processing each element of the list. It ensures that all elements are accessed in sequence.

Understanding traversal is a foundational step for more advanced linked list algorithms, including deletion, reversal, and cycle detection.

Key Insight: Traversal is the basis for all linked list operations—ensure you visit every node, and beware of cycles that can cause infinite loops.

Traversal Types

Iterative Traversal

Complexity: O(n)

Uses a loop to traverse from head to end of list

function traverseIterative() {
  let current = head;
  while (current) {
    console.log(current.data);
    current = current.next;
  }
}

Recursive Traversal

Complexity: O(n) and O(n) space (due to recursion stack)

Uses recursion to print each node from head to end

function traverseRecursive(node) {
  if (!node) return;
  console.log(node.data);
  traverseRecursive(node.next);
}

Traversal Process

Start from the head node
Access the data of the current node
Move to the next node using the next pointer
Repeat until the current node becomes null

Operation Visualization

Operation	List State
Initial State	head → [A] → [B] → [C] → null
Traverse	Visited: A → B → C

Edge Cases to Consider

Empty list (head = null)

Single-node list (head → [A] → null)

List with cycles (can cause infinite traversal if not handled)

Recursive traversal stack overflow for large lists

Best Practices

Always check if the list is empty before traversal

Avoid infinite loops by checking for cycles

Use iteration for large lists to prevent stack overflow

Keep traversal read-only unless modifying the list is necessary

Separate logic for display and manipulation for better modularity

Comparison with Array Traversal

Feature	Array	Linked List
Time Complexity	O(n)	O(n)
Access Method	Direct via index	Sequential via next pointer
Recursion Friendly	Not typically used recursively	Supports recursive traversal
Loop Detection Required	Not needed	May be necessary in some cases

When to Choose: Use arrays for indexed, direct access and linked lists for flexible sequential access and recursive algorithms.

Implementation Notes

Cycle Detection: Be cautious of loops in the list during traversal, consider Floyd’s algorithm for detection
Logging: Use console or UI to log visited nodes during visualization
Testing: Test traversal on empty, single-node, and multi-node lists
Efficiency: For large lists, prefer iteration to avoid stack issues with recursion

Visualize how we traverse through each node in a linked list

Node

Visited

Address

Pointer

Click "Generate List" to create a linked list 🌈

Test Your Knowledge Before Moving Forward!

Traversal Quiz Challenge

How it works:

+1 point for each correct answer
0 points for wrong answers
-0.5 point penalty for viewing explanations
Earn stars based on your final score (max 5 stars)

Linked List Insertion Implementation

class Node {
  constructor(data) {
    this.data = data;
    this.next = null;
  }
}

function traverse(head) {
  let current = head;
  while (current) {
    console.log(current.data);
    current = current.next;
  }
}

let head = new Node(1);
head.next = new Node(2);
head.next.next = new Node(3);
traverse(head);

Explore Other Operations

Insertion

Deletion

Compare

Merge

Searching

Reverse