Trees & Linked Lists

Trees and linked lists are the classic core of a Microsoft coding loop. The same handful of problems keep surfacing, year after year and across regions: reverse a linked list, a Premium question, serialize and deserialize a binary tree, diameter, and a Premium question. Microsoft leans easier and more classic than Google or Meta, so the bar here is clean, bug-free pointer and recursion code rather than an exotic trick.

Code usually runs in a Microsoft round, so a missed null check or an off-by-one in your pointer rewiring shows up the moment you hit execute. Correctness on the edges is what decides these. Right base cases, and pointers that stay consistent through every step. Two templates cover almost all of it; the rest is recognizing which one a problem wants.