Merge

2 articles

dsa8 min read

Merge Two Sorted Lists — The Dummy Head Pattern Every Interview Expects

LC 21 Merge Two Sorted Lists is one of the most frequently asked linked list interview problems at Amazon, Google, and Microsoft. Learn the dummy head merge pattern with step-by-step Python and JavaScript solutions, visual dry run, and interview tips.

March 19, 2026Read →

dsa8 min read

Reorder List — Split, Reverse, Merge in One Pass

LC 143 Reorder List is a composite interview problem at Facebook, Amazon, and Google that combines three core patterns: fast/slow midpoint finding, in-place second-half reversal, and interleaved merging. Master the O(1) space solution with Python and JavaScript, step-by-step visual trace, and interview approach.

March 19, 2026Read →