Threads and Race Conditions

Concurrency comes up across the xAI loop, from a 15-minute screen to ML infrastructure rounds. The three tasks here run from a short warm-up to a hard distributed one.

The code for each is small. The questions after it go deeper, and you should expect to explain why an update went missing and what each lock covers. Hold one lock across each read and write of shared state, and join every thread before you merge results.

A race can pass a test run and still be wrong. So reason about it out loud, naming the shared state first and then the lock that guards it. If you're writing Python, also say what the GIL does to threads that only compute.

xAIPremium lesson · Coding round

The 3 xAI problems are below.

1. 1A Premium questionCoding · Easy
2. 2A Premium questionCoding · Medium
3. 3A Premium questionCoding · Hard

Each with hints, the follow-up and a tested solution.

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