DSA Problems Progress Plan Roadmaps Review Cheat Sheets Companies System Design CS Fundamentals Question Bank

Theme

Microsoft question bank

Fundamentals-first: linked lists, trees, and clean implementation — plus a practical design conversation.

14 DSA problems · 2 system-design prompts · compiled from publicly shared interview experiences; exact questions vary between loops.

Reverse Linked ListEasyLinked ListsVery common

Iterative and recursive, then reverse-in-groups follow-up.linked-listrecursion

Linked List CycleEasyLinked ListsVery common

linked-listtwo-pointers

Merge Two Sorted ListsEasyLinked ListsVery common

linked-listrecursion

Binary Tree Level Order TraversalMediumTreesVery common

Zigzag variant is the usual follow-up.treebinary-treebfs

Valid ParenthesesEasyStringsCommon

Validate Binary Search TreeMediumTreesCommon

treebinary-search-treedfs

Lowest Common Ancestor of a BSTMediumTreesCommon

treebinary-search-tree

Rotate ArrayEasyArraysCommon

Expect the O(1)-space reversal trick.arraytwo-pointersmath

Majority ElementEasyArraysCommon

Boyer–Moore voting earns points.arrayhash-tabledivide-and-conquer

Longest Common SubsequenceMediumDynamic ProgrammingCommon

dynamic-programmingstring

Design Dropbox / Google DriveCommon

File sync design fits the OneDrive org.

LLD: Design an Elevator SystemCommon

Recurring LLD prompt.

First Missing PositiveHardArraysOccasional

arrayhash-tablecyclic-sort

Gas StationMediumGreedyOccasional

Implement Queue using StacksEasyStacks & QueuesOccasional

Design-flavored warm-up.stackqueuedesign

Binary Tree Maximum Path SumHardTreesOccasional

Senior-loop hard.treebinary-treedfsdynamic-programming