Multi-Level Coding Round Practice

The coding round in Anthropics FDE loop gives a candidate one problem that grows. Each level adds requirements to the code from the level before, and the next level opens only after every test on the current one passes. Algorithm puzzles rarely appear. The problems are small, practical systems, such as a key-value store, a banking ledger, or a rate limiter.

That format rewards one skill above the rest. A candidate whose first version is rigid spends the later levels rewriting it. A candidate whose first version is plain and open spends them adding small methods. The practice problem below builds that habit across four levels.

How the round works

CodeSignal is an online platform that companies use to run timed coding assessments in a browser-based editor. Its Industry Coding Framework is a format where one project grows across four levels, each adding new methods and requirements. Anthropics round most often runs as a timed CodeSignal assessment in this format. Some teams run a live version instead, in a shared editor with an interviewer watching. The rules below hold for the timed assessment, and the format can vary by team, so the recruiter is the best source for the exact setup.

• One problem, four levels: The whole round is a single project, and later levels are harder and worth more points.

• About 90 minutes: The clock covers all four levels, and many candidates run out of time on level 4.

• Tests unlock levels: Each levels unit tests are visible, and the next level opens only after all of them pass.

• Earlier methods keep working: New levels add methods and change rules, and every earlier test still has to pass.

• Python standard library: Solutions use plain Python, with no outside packages.

• Scored from 200 to 600: A score around 520 or higher usually moves a candidate forward.

• Code is reviewed: Submissions are checked for hardcoded outputs and branches written only to pass a specific test. ...