Discover how a single character difference in duplicate-skipping logic can silently break your Four Sum solution. Learn why j > 1 fails across different loop iterations and how j > i + 1 ensures all valid quadruplets are found through real debugging examples.
Discover why nums[-1] doesn't crash JavaScript and how understanding arrays as objects can help you debug algorithm problems like 3Sum. Learn about negative indexing, property access patterns, and JavaScript's unique array behavior.
Master Floyd's cycle detection algorithm for finding cycle entry points in linked lists. Covers both compact interview solution and teaching-friendly implementation with mathematical intuition.
Master two iterative approaches for swapping adjacent nodes in linked lists: straightforward pointer manipulation vs elegant dummy head technique for cleaner code.
Compare two approaches to removing the nth node from the end of a linked list: explicit length counting versus elegant two-pointer technique with dummy head pattern.
Master the two-pointer technique for reversing linked lists. Learn how each step involves three nodes and one edge flip, with iterative implementation and common pitfalls.
Learn to implement a clean, maintainable linked list in JavaScript using the dummy head pattern. Compare straightforward vs elegant approaches, understand sentinel design principles, and discover when to apply this powerful technique across algorithms and data structures.
Understanding the sentinel node pattern as a powerful algorithmic technique that simplifies boundary cases across data structures, algorithms, and programming paradigms.
Master LinkedList implementation in JavaScript with classes vs factories. Complete guide to constructor, this, and choosing the right approach for algorithms vs production.
A deep dive into solving linked list deletion problems, comparing approaches with and without dummy head nodes, including my mistakes and key takeaways.
Master JavaScript array initialization to avoid mysterious bugs in algorithms and dynamic programming. Learn the difference between mutable references and immutable primitives.
Learn the sliding window technique through the classic Minimum Size Subarray Sum problem. Understand how two pointers can optimize O(n²) brute force to O(n) efficiency.
Decode the elegant layer-by-layer approach to generating spiral matrices. Learn how to think in concentric rings and avoid complex edge cases with clean, scalable code.
Explore the evolution of sum problems from 2Sum to generalized KSum through real-world analogies, code evolution, and optimization techniques.
Elements Filtering, Elements Replacements, Elements Reordering, Partitioning..