Hot100: Merge K Sorted Lists Divide-and-Conquer O(N log k) ACERS Guide

Subtitle / Summary LeetCode 23 is a k-way merge problem, not just repeating LeetCode 21 in a loop. This ACERS guide derives the optimal structure, explains tradeoffs between divide-and-conquer and min-heap, and provides runnable implementations in multiple languages. Reading time: 12-16 min Tags: Hot100, linked list, divide and conquer, merge SEO keywords: Merge K Sorted Lists, LeetCode 23, divide and conquer, O(N log k), Hot100 Meta description: A full ACERS explanation of Merge K Sorted Lists from naive ideas to O(N log k) divide-and-conquer, with engineering mapping and multi-language code. Target Readers Hot100 learners who have finished LeetCode 21 and want the next-level merge template Developers who need predictable performance for k-way ordered data merge Engineers preparing for linked-list and divide-and-conquer interview rounds Background / Motivation This problem appears in many production forms: ...

February 10, 2026 · 11 min · map[name:Jeanphilo]

Sorting Series (6): Heap Sort - In-place O(n log n) with Worst-Case Guarantees

Explain heap sort principles, complexity, and engineering scenarios; compare with quick/merge; include multilingual implementations and top-k examples.

December 6, 2025 · 5 min · map[name:Jeanphilo]