Small questions. Stronger foundations.

Eight questions across engineering and interview skills. Get an explanation for every answer.

The foundations checkpoint

0 of 8 answered · About 8 minutes

QUESTION 1

A worker commits a database change, then crashes before acknowledging the message. What protects a retry?

A longer queueAn idempotency key and atomic deduplicationMore worker replicasA shorter timeout

QUESTION 2

Which traversal finds the shortest path in an unweighted graph?

Depth-first searchBinary searchBreadth-first searchTopological sort

QUESTION 3

Which signal would leak future information into a fraud model?

Transaction amountAccount age at transaction timeChargeback recorded after the transactionPrior transaction count

QUESTION 4

A fixed-size heap is especially useful for which task?

Finding every connected componentMaintaining the top K values in a streamSorting linked-list pointersFinding a substring

QUESTION 5

What is strongest in a behavioral answer about disagreement?

Proving your colleague was wrongAvoiding any discussion of conflictExplaining shared goals, evidence and the resulting decisionListing every person in the meeting

QUESTION 6

Why separate retrieval from ranking in recommendations?

To avoid collecting any dataTo rank every item synchronouslyTo cheaply narrow the candidate set before expensive scoringTo eliminate evaluation

QUESTION 7

Which design protects a seat from being sold twice?

A cache TTLAn atomic conditional reservationA read replicaA nightly cleanup

QUESTION 8

When reviewing AI-generated code, what should happen first?

Accept it if it compilesRead the change against requirements and run focused checksAsk for a complete rewriteRemove the existing tests

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