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

400 Bad Request

Answer

409 Conflict

Answer

412 Precondition Failed

Question 2

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

Accepted Answer

Read Committed

Answer

Read Uncommitted

Answer

Serializable

Answer

Repeatable Read

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

A class should have only one reason to change

Answer

High-level modules should not depend on low-level modules

Answer

A class should not be forced to implement interfaces it does not use

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

AVL Tree

Answer

Sorted Array

Answer

Skip List

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

The remote branch has been deleted

Answer

The local repo has merge conflicts

Answer

HEAD points to an orphan branch with no commits

Question 6

Which Big-O complexity describes inserting an element at the beginning of a singly linked list?

Accepted Answer

O(1)

Answer

O(n)

Answer

O(log n)

Answer

O(n log n)

Question 7

In a microservices architecture, the Saga pattern is primarily used to:

Accepted Answer

Manage distributed transactions across multiple services without two-phase commit

Answer

Cache inter-service responses for performance

Answer

Load-balance requests between service replicas

Answer

Encrypt messages passed over the service mesh