James A Rosen

Staff Engineer, AI Systems

James A Rosen, pixelated, wearing a bow tie

DSA Interview Prep

A personal study log of DSA interview prep, tutored by Claude. Each lesson covers a topic through concept explanation, hands-on implementation, and classic interview problems.

3 lessons
3 topics
15 problems

Lessons

  1. Lesson 1: Diagnostic Assessment

    Eight classic interview problems across heaps, graphs, DP, and data structure design — used to identify gaps before building a study plan. Result: strong first-principles reasoning, weak pattern recognition.

    Diagnostic 8 problems
  2. Lesson 2: Heaps

    Heap internals (array representation, sift-up/down, O(n) heapify) plus a generic TypeScript implementation. Applied to Meeting Rooms II and Find Median from Data Stream, with a lightning round to calibrate heap vs. heap-adjacent patterns.

    heaps 3 problems
  3. Lesson 3: BFS and DFS on Graphs and Grids

    Covered BFS (queue) and DFS (recursion/stack) traversal patterns on graphs and grids. Key takeaway: BFS guarantees shortest path in unweighted graphs because distance from source equals level depth; mark nodes visited on enqueue, not dequeue.

    BFS/DFS 4 problems