Linked List Data Structures and Algorithms for Interviews

Insert at the beginning of a linked list by creating a new node and setting its next to the former head. Then update the head to the new node.

Traverse the list from the head, print each element, and follow the next pointers until reaching the end. Achieve O(n) time by performing a single linear traversal for n elements.

insert a node at the end of a linked list. use a tail pointer for constant-time insertion, or traverse from head to the last node, updating head and tail.

Learn to insert a node at the kth position in a linked list, covering insertion at the beginning, end, and middle with head pointer updates.

Learn how to reverse a singly linked list iteratively using current, previous, and next pointers, handling head and null safely while observing the list before and after reversal.

Explore reversing a singly linked list recursively, handling base cases, dividing the list into head and sublist, and reconnecting next pointers to yield the reversed list.

Check if a singly linked list is a palindrome by reversing the first half with slow and fast pointers and then comparing with second half, handling even and odd lengths.

Detect loops in a linked list and determine if the list is cyclic. Apply fast and slow pointer techniques (Floyd's algorithm) or hash map approaches to detect a cycle.

Show how to count the number of elements in a loop in a linked list using slow and fast pointers, and confirm loop presence with Floyd cycle detection.

Apply Floyd's cycle detection with slow and fast pointers to locate a loop in a linked list and identify the starting element of the loop.

Apply Floyd's cycle detection using fast and slow pointers to identify a loop in a linked list, locate the first node of the loop, and analyze loop length and distances.

Discover how to detect and remove a loop in a linked list using slow and fast pointers, locate the first loop node, and adjust pointers to break the cycle.

Learn to find the middle element of a linked list using slow and fast pointers, handling even and odd lengths and no-loops scenario, with step-by-step examples.

Explore two methods to find the kth node from the end in a singly linked list: a two-pass scheme and a single-pass two-pointer approach, with edge-case handling.

Determine if a linked list is a palindrome by comparing mirrored elements. Use a stack or a middle-find and reverse-half approach with two pointers for O(n) time and O(1) space.

Swap nodes of a linked list in constant time by reassigning next and previous pointers, updating the head when needed, without copying data.

Group the odd and even nodes of a linked list in linear time using constant extra space, then connect the two lists to form the final list.

Delete a node in a linked list without head pointer by copying the next node's data into the target node and bypassing the next node, achieving constant time and space.

Remove all nodes with a given value from a singly linked list in one pass, including head deletions, using iterative and recursive approaches.

Reverse a linked list in groups of K, leaving any remainder unreversed, while tracking head, tail, current, next, and previous to connect each block.

Explore how doubly linked lists store data with next and previous pointers. Experience bidirectional traversal and easier insertion and deletion, though it uses more memory than singly linked lists.

Flatten a multi-level doubly linked list by recursively flattening each child and inserting it after the current node, updating next and previous pointers and returning the tail for seamless integration.