Demystifying Linked Lists: A Practical Approach

A cycle in a linked list occurs when a node points back to an earlier node instead of nil, creating a loop with no end. This can lead to infinite loops during traversal, memory issues, and incorrect algorithm behavior. Cycles are often introduced unintentionally and must be detected to avoid logic errors in list operations.

This Swift example demonstrates how to detect a cycle in a generic singly linked list using Floyd’s Cycle Detection Algorithm (Tortoise and Hare). The hasCycle function uses two pointers—one slow and one fast—to traverse the list. If the two pointers ever meet, a cycle is present. In the sample setup, a cycle is intentionally created by linking the last node back to a previous node. The function then correctly detects and reports the cycle.

This Swift function finds the middle node of a singly linked list using a fast and slow pointer approach. The slow pointer advances one step at a time, while the fast pointer moves two. When the fast pointer reaches the end, the slow pointer is at the middle. This efficient one-pass algorithm handles both even and odd-length lists, returning the second middle node in even-length cases. Ideal for technical interviews focused on pointer logic and time-space optimization.

In this video, watch as I walk through how to code a Swift function that finds the middle node of a singly linked list. Using the fast and slow pointer technique, I show how to implement the solution step by step, explain the logic behind it, and test it with example data. This is a great exercise for mastering pointer manipulation and preparing for technical interviews.

In this lesson, you'll learn what pointer manipulation means in Swift and why it's essential for working with data structures like linked lists. While Swift hides raw pointers, class instances behave like references—allowing you to reassign .next pointers to change relationships between nodes.

You'll explore real-world examples like inserting, removing, and reversing nodes in a linked list, and learn how these operations rely on correctly managing object references. This foundational skill is key to writing safe and efficient Swift code involving custom data structures.

In this video, you'll learn how to write a Swift function to remove the n-th node from the end of a singly linked list using a two-pointer technique. We'll walk through creating a dummy node, advancing a fast pointer n steps ahead, and using a slow pointer to find the node to remove—all in a single pass. This efficient solution is ideal for technical interviews and mastering pointer-based list manipulation in Swift.

In this video, we walk through how to determine if a singly linked list is a palindrome using Swift. You'll learn how to apply fast and slow pointers to find the middle of the list, reverse the second half in-place, and compare both halves to check for symmetry. This solution is optimized for O(n) time and O(1) space, making it ideal for coding interviews and mastering linked list techniques in Swift.

In this course, you'll learn how to merge two sorted singly linked lists into one sorted list by directly manipulating node references—without allocating new nodes. This problem challenges you to apply pointer-based logic, understand list traversal, and compare node values efficiently. You'll explore both iterative and recursive approaches, reinforcing your ability to work with class-based structures in Swift. Ideal for technical interviews, this lesson emphasizes clean, performant, and in-place solutions with O(n + m) time complexity.

In this lesson, you'll learn how to merge two sorted singly linked lists in Swift using an efficient in-place approach.We’ll implement a generic function that preserves node structure, runs in O(n + m) time, and uses constant space. By the end, you’ll understand how to manipulate linked list pointers effectively without creating new nodes.

In this lesson, you'll learn how to merge two sorted singly linked lists in Swift using an efficient in-place approach.We’ll implement a generic function that preserves node structure, runs in O(n + m) time, and uses constant space. By the end, you’ll understand how to manipulate linked list pointers effectively without creating new nodes.