Linked Lists and Pointer Manipulation Questions

Comprehensive knowledge of linked list data structures and pointer based implementations. Covers singly linked lists, doubly linked lists, circular lists, and node based sequential structures. Candidates should be able to implement and reason about core operations including traversal, insertion, deletion, reversing a list, finding the middle element, removing the nth node from the end, detecting and removing cycles, merging sorted lists, partitioning lists, computing intersection nodes, and other in place transformations. Emphasize pointer and reference manipulation techniques, manual memory allocation and deallocation, ownership and lifetime considerations, and debugging strategies for pointer errors and memory leaks, particularly in manual memory management languages such as C and C plus plus. Also cover implementation techniques such as iterative and recursive approaches, use of dummy head or sentinel nodes to simplify edge cases, and in place algorithms to minimize extra memory. Discuss algorithmic complexity and trade offs relative to contiguous arrays, including dynamic resizing, memory locality, and cache behavior, and when linked lists are the appropriate abstraction such as in embedded systems or when implementing free lists and adjacency lists. Interviewers may probe both low level pointer manipulation and higher level reasoning about when to use list based structures and how list concepts extend into more complex data structures.

MediumTechnical

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You must maintain the last `k` records seen from a very large stream using node-based structures. Design an approach using linked lists (or an alternative) to support O(1) insertion and O(1) removal of the oldest record, with occasional random reads within the last `k`. Compare a circular linked list vs a ring buffer array for performance and memory usage.

MediumTechnical

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Design a simple free-list allocator for fixed-size objects used in a C application: describe the in-memory data structures (single linked free list), allocation and free algorithms, alignment considerations, and strategies to reduce contention and fragmentation in a multi-threaded data ingestion process.

HardSystem Design

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Design a thread-safe append-only queue where producers append to tail and consumers pop from head. Compare a simple mutex-based linked-list queue with a lock-free Michael-Scott queue: describe pointer manipulations, necessary memory reclamation, and expected throughput characteristics in a high-concurrency ingestion system.

MediumTechnical

0 practiced

Explain how sentinel (dummy) head/tail nodes simplify linked-list code. Show example scenarios for insertion and deletion where a dummy node removes special-casing of head/tail handling, and discuss any downsides and memory overhead of this approach.

MediumTechnical

0 practiced

Design a compact binary format and implement high-level pseudocode to serialize and deserialize a singly linked list to/from disk. Your format should include node payload and the next-node offset so the list can be restored across process restarts. Explain how you handle endianness, versioning, and detecting corruption.

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