Interview Questions

Questions that I've either worked through, received in real or mock interviews, given in real or mock interviews, or would like to work through at some point.

Coding

• Serialize and deserialize an n-ary tree

System design

• ngrok: dynamically provision a reverse proxy to localhost:8080

• internal webhook delivery platform: allow internal services to deliver webhooks to user-provided webhook handler endpoints

• location proximity search: given a dataset of locations, return the ones nearest to the user

• top N currently streaming songs: show the top N, in order, along with the active stream count (some inaccuracy is OK), in real-time

• schedule send, a la email, Slack, or text

Some notes about system design

System design is hard

• because identifying The Hard Problems™ is hard,
• because breaking down a problem into easy problems is hard, and
• because reasoning about edge cases and failure modes is hard.

Your job as a candidate is to demonstrate that you are capable of all this.

<rant>

Also, FYI: most system design resources on the internet are terrible.

• They usually take the form "given assumptions A, B, and C, this is The Correct Way to solve this problem". A competent engineer can say "assuming A1 xor A2, here's how my design would change".

• A lot of them suggest doing resource estimates, e.g. "given 2M entries, 5 bytes overhead, 33 bytes each, we need XYZ storage", but that's (naive) capacity planning, not system design. Do a Fermi estimate and move on.

</rant>