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Interview questions from top companies, mapped to the exact round they show up in. Prep for what you will actually face.

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Online AssessmentDSA / CodingMachine CodingLow-Level Design

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The Loop aggregates publicly shared interview experiences and curated commonly-asked questions, each labeled with its source. Not affiliated with any company listed.

CC BY-NC 4.0 · © 2026

← Sierra

Staff+ Backend at Sierra

BackendStaff+Offer◆ Commonly asked· 2024

5-round staff backend process. Fundamentals mattered as much as getting to an answer.

The loop · 5 rounds

01

Round 01 · 3 questions

DSA / Coding

Data structures & algorithms on a whiteboard or shared editor.

  • Best time to buy and sell stock.
    Staff+Easy◆ Commonly asked
    #array#greedy
    PracticeLeetCode↗GeeksforGeeks↗
  • Daily temperatures.
    Staff+Medium◆ Commonly asked
    #stack#monotonic-stack
    PracticeLeetCode↗GeeksforGeeks↗
  • Reverse nodes in k-group.
    Staff+Hard◆ Commonly asked
    #linked-list
    PracticeLeetCode↗GeeksforGeeks↗
02

Round 02 · 1 question

Low-Level Design

Object-oriented / low-level design of a focused module.

  • Design an ATM / cash dispenser.
    Staff+Medium◆ Commonly asked
    #oop#state-machine
    PracticeGeeksforGeeks↗Search↗
03

Round 03 · 2 questions

System Design

High-level architecture of a large-scale system.

  • Design a distributed cache.
    Staff+Hard◆ Commonly asked
    #cache#consistency
    PracticeGeeksforGeeks↗Search↗
  • Design a ride-sharing service like Uber.
    Staff+Hard◆ Commonly asked
    #geospatial#matching
    PracticeGeeksforGeeks↗Search↗
04

Round 04 · 1 question

Hiring Manager

Scope, ownership, and role-fit discussion with the manager.

  • Walk me through the architecture of a system you owned end to end.
    Staff+◆ Commonly asked
    #ownership#architecture
05

Round 05 · 2 questions

Behavioral / HR

Values, collaboration, and past-experience (STAR) questions.

  • Tell me about a time you failed and what you learned.
    Staff+◆ Commonly asked
    #growth#star
  • When did you change your mind after seeing new evidence?
    Staff+◆ Commonly asked
    #judgment#star

Practice each round across every company

  • DSA / Coding
  • Low-Level Design
  • System Design
  • Hiring Manager
  • Behavioral / HR

◆ This experience is composed from commonly reported questions for this role and level. Real, individually-shared interviews will be layered in over time.