Microsoft SDE-1 off-campus — Tic-Tac-Toe LLD and a URL shortener

## Background
I applied directly through the Microsoft careers portal using a referral from a senior contact.

## Resume shortlisting
My internship experience at a couple of well-known tech companies seemed to carry real weight at this stage.

## Online assessment
Coding problems around two medium and one hard. To clear it I needed to solve them completely rather than partially.

## Round-by-round
*(All three rounds on the same day, roughly 45 minutes each.)*

### Technical round 1 — Low-level design
Design a simple two-player grid-based game (think Tic-Tac-Toe): class structure, relationships, and how game state would be managed. The follow-up was to extend it with logic for the optimal move at any state, which meant a game-tree-based decision algorithm.

There was also a coding question on rotating a 2D matrix — **in place**, modifying the original rather than creating a new one.

### Technical round 2 — System design
Designing a large-scale **URL-shortening service**: how the mapping between short and long URLs works, handling billions of unique addresses, what hashing strategy makes sense, and edge cases at that scale.

### Managerial round
Technical and behavioural. On the technical side, networking fundamentals — DNS, HTTP, the three-way handshake, TLS/SSL. On the behavioural side, academic background and internships in more depth.

## Verdict
**Selected.**