CodeSignal Technical Assessment Domain-Specific Knowledges 2

Question 1

In a REST API, which HTTP status code indicates that the client's request was syntactically correct but semantically invalid (e.g., a business rule violation)?

Accepted Answer

422 Unprocessable Entity

Answer

422 Unprocessable Entity is used when the request is well-formed but contains semantic errors that prevent processing.

Question 2

Which SQL isolation level prevents dirty reads but still allows non-repeatable reads?

Accepted Answer

Read Committed

Answer

Read Committed prevents reading uncommitted (dirty) data but allows another transaction to modify rows between two reads in the same transaction.

Question 3

In object-oriented design, the Liskov Substitution Principle states that:

Accepted Answer

Objects of a superclass should be replaceable with objects of its subclasses without breaking correctness

Answer

LSP requires that subclasses honor the behavioral contracts of their parent classes so callers can rely on polymorphism safely.

Question 4

Which data structure offers O(1) average-case insertion and lookup but O(n) worst-case due to hash collisions?

Accepted Answer

Hash Table

Answer

Hash tables achieve O(1) average operations but degrade to O(n) when all keys hash to the same bucket.

Question 5

In Git, what does a 'detached HEAD' state mean?

Accepted Answer

The HEAD pointer references a specific commit rather than a branch

Answer

Detached HEAD means HEAD points directly to a commit SHA instead of a named branch ref, so new commits won't belong to any branch.

Codesignal Practice Test

Codesignal Practice Test

CodeSignal Technical Assessment Domain-Specific Knowledges 2