Remove Loop in Linked List

In this video, we explore how to detect and remove loops in a linked list. A loop in a linked list occurs when a node's next pointer points back to one of the earlier nodes, causing an infinite cycle. We discuss two main approaches to handle this problem: Using Hashing and Floyd’s Cycle Detection Algorithm. In the naive approach, we traverse the linked list and store each node in a hash set. If we encounter a node already in the hash set, we can remove the loop by setting the next pointer of the previous node to NULL.

We also dive into the efficient approach using Floyd’s Cycle Detection Algorithm, also known as the Tortoise and Hare algorithm. This approach uses two pointers: one moving one step at a time (slow pointer) and the other moving two steps at a time (fast pointer). If the fast pointer meets the slow pointer, we detect a loop. To remove the loop, we reset the slow pointer to the head of the list and move both pointers one step at a time until they meet at the node where the loop starts. Once identified, we can remove the loop by setting the next pointer of the loop’s last node to NULL. This method has a time complexity of O(n) and space complexity of O(1), making it efficient for large lists.

For more details, please go through - Detect and Remove Loop in Linked List