LeetCode pros deploy slow-fast pointers to detect linked list cycles—finally escaping the infinite loop of tech interviews and startup pivots

A recent solution to LeetCode problem 141, "Detecting a Cycle in a Linked List," highlights the effectiveness of the two-pointer technique in identifying cycles in linked lists. Given the head of a singly linked list, the task is to return true if a cycle exists and false otherwise, without modifying the list. The two-pointer approach, where one pointer moves one step at a time and the other moves two steps, can efficiently detect cycles. If a cycle exists, the fast pointer will eventually catch up to the slow pointer, while if there is no cycle, the fast pointer will reach NULL. This solution has a time complexity of O(n), making it the most optimal solution. In the context of linked list problems, the fast and slow pointer technique is often preferred in interviews, as it avoids using extra memory and relies on movement patterns to reveal the structure of the list.