Saturday Questions | Python DSA Practice

Saturday Questions: Linked Lists in Python

This edition is focused only on linked lists: nodes, next pointers, traversal, insertion, deletion, reversing, middle node, cycle detection, merging sorted lists, and removing the nth node from the end.

Linked lists are important because they teach students to think beyond array indexing. They build real pointer discipline.

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What you will learn

  • Node creation
  • Traversal
  • Search
  • Insertion and deletion
  • Pointer updates

Interview patterns

  • Reverse linked list
  • Slow and fast pointer
  • Cycle detection
  • Merge two sorted lists
  • Remove nth from end

Main idea

A linked list is a chain of nodes. Every safe solution depends on preserving the next pointer before changing links.

The basic linked list pattern

current = head
while current is not None:
    print(current.data)
    current = current.next
In linked lists, movement happens through next. There is no direct jump to index 5 like a normal Python list.

Questions included

  1. Build and display a linked list
  2. Count nodes
  3. Search a value
  4. Insert at beginning and end
  5. Delete first occurrence
  6. Reverse a linked list
  7. Find the middle node
  8. Detect a cycle
  9. Merge two sorted linked lists
  10. Remove the nth node from the end

Practice area

Use the embedded practice viewer below. Try every question first, then compare with the explanation and final code.

Saturday Questions ViewerOpen full screen

Why linked lists matter

Linked list questions reveal whether a student understands state changes. In arrays, many operations feel automatic. In linked lists, every arrow must be handled intentionally.

This is why linked lists are still a useful interview topic. They test clarity, patience, and disciplined pointer movement.