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Quest Diagnostics Software Engineer Interview Questions

The questions to prepare for a Quest Diagnostics Software Engineer interview. Questions from real interview reports rank first. Updated daily.

28questions
~4htotal time
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1
CodingStart here. 8 questions · ~71 min
Linked List ReversalEasy
Practice

Reverse a singly linked list in-place using iterative pointer manipulation.

RecursionLinked ListsArraysQuest Diagnostics
Java 8 vs Earlier VersionsEasy

Compare Java 8 with earlier Java versions, focusing on lambdas, functional interfaces, streams, and API improvements.

javabasicstechnical fundamentalsQuest Diagnostics
Fail-Fast vs Fail-Safe IteratorsMedium

Evaluates your understanding of iterator behavior and how it impacts correctness.

iteratorsData StructuresQuest Diagnostics
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2
SQL & Data Manipulation3 questions + 3 drills · ~57 min
SQL Server Performance TuningMedium

Tests your ability to diagnose and optimize SQL Server performance in production systems.

sql performanceQuest Diagnostics
Primary Key vs Unique KeyEasy

Tests database schema knowledge and constraints relevant to data integrity.

JoinsData WranglingQuest Diagnostics
Optimize a Slow SQL QueryMedium

Tests SQL performance troubleshooting and query optimization strategies.

Window FunctionsJoinsAggregationsQuest Diagnostics
7-Day Rolling Average with Window FunctionsMedium
Practice
Practice drill

Calculate daily and 7-day rolling operational downtime for the Siemens Healthineers SOMATOM CT product line.

Window FunctionsDate FunctionsRunning TotalsSiemens HealthineersCogniteRakuten Symphony
Your Data ProjectMedium
Practice
Practice drill

Use joins, aggregation, and a CTE to identify TikTok Shop sellers with at least two completed orders.

experienceJoinsData ManipulationTikTokTikTok Shop
Top Daily Rides by VehicleMedium
Practice
Practice drill

Rank the top 3 completed rides per vehicle per day using joins, a CTE, and ROW_NUMBER.

Window FunctionsJoinsData WranglingWaymoCruise

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3
Behavioral & Leadership15 questions · ~133 min
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4
More topics2 questions · ~18 min
Securing a REST APIHard

Tests secure API design, authentication, authorization, and threat mitigation for healthcare microservices.

InfrastructureNetworkingQuest Diagnostics
Java Memory ManagementMedium

Tests understanding of Java runtime memory management and garbage collection concepts.

Infrastructureos internalsQuest Diagnostics
The finish line: interview-readyComplete all 28 questions plus 3 hands-on drills to finish this plan.