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LinkedIn QA Engineer Interview Questions

43 practice questions for LinkedIn QA Engineer interviews

LinkedIn QA engineer interviews test automation frameworks, test strategy, CI integration, performance testing, and debugging complex multi-service systems.

All Roles Software Engineer Backend Engineer Frontend Engineer Full Stack Engineer Mobile Engineer Data Engineer Data Scientist ML Engineer DevOps Engineer DevOps Engineer Product Manager SRE Security Engineer Engineering Manager Data Analyst UX/UI Designer QA Engineer
coding Easy Verified Question #1

1. Balanced Parentheses


Category: String coding problem
Configuration files at LinkedIn are written in JSON, YAML, and HOCON formats. Malformed config files can bring down multiple services, so validators...
Input: String
Output: Printed output
coding Medium Verified Question #2

2. Words From Phone Number


Category: String coding problem
A standard phone keypad maps digits to letters as follows: ` 2 -> a, b, c 3 -> d, e, f 4 -> g, h, i 5 -> j, k, l 6 -> m, n, o 7 -> p, q, r, s 8 ->...
Input: List
Output: Array
coding Medium Verified Question #3

3. Circular Signal Window


Category: Array coding problem
You are given a circular array signal of 0s and 1s representing antenna readings logged in sequence, where 1 means good signal and 0 means...
Input: Array
Output: Integer
coding Easy Verified Question #4

4. Active Sprint Filter


Category: Graph coding problem
A project tracking system logs team activity throughout the workday. Each log entry has the format "teamId action timestamp", where action is...
Input: Graph (nodes and edges)
Output: Printed output
coding Medium Verified Question #5

5. Dependency Task Executor


Category: Graph coding problem
A build system manages pipeline steps where each step may depend on other steps completing first. Implement the BuildPipeline class:...
Input: Graph (nodes and edges)
Output: Computed result
coding Medium Verified Question #6

6. Daily Branch Pruning


Category: Tree coding problem
A file system manages a directory tree. Each day, all leaf directories (those with no child directories) are simultaneously removed. Directories that...
Input: Array
Output: Array
coding Hard Verified Question #7

7. [OA] Minimum Weight Ceiling Path


Category: Graph coding problem
A network topology connects n servers labeled 1 to n. Each connection is a bidirectional link with a bandwidth cost. A network engineer needs...
Input: Graph (nodes and edges)
Output: Integer
coding Hard Verified Question #8

8. Priority Cache System


Category: String coding problem
A CDN (Content Delivery Network) maintains a fixed-capacity cache of web content. Each content item has an associated priority score. When the cache...
Input: String
Output: Integer
coding Medium Verified Question #9

9. Distribution Center Placement


Category: Array coding problem
A logistics company is expanding its distribution network along a single highway. You are given an array of integers locations representing the...
Input: Array of integers
Output: Computed result
coding Medium Verified Question #10

10. Manual String Substitution


Category: String coding problem
A template engine needs to substitute all occurrences of a pattern in a template string with a replacement string, without using any built-in...
Input: String
Output: Printed output
coding Hard Verified Question #11

11. Combine N-ary Trees


Category: Tree coding problem
You are given the roots of two N-ary organization charts, each representing a hierarchical department structure. Every node has an integer...
Input: List
Output: Computed result
coding Medium Verified Question #12

12. Closest Value Pair


Category: Array coding problem
An inventory system has two sorted product catalogs A and B. Each value in the catalog represents a product size. Find a pair [a, b] where a...
Input: Array
Output: Computed result
coding Medium Verified Question #13

13. Digit Replacement Maximizer


Category: String coding problem
A numeric optimization system performs exactly k substitution operations on a number string s. In each operation, choose any digit in s that is...
Input: String
Output: Computed result
coding Hard sliding window #1

1. [OA] Binary Search — Implement a Flaky Test Detector used in LinkedIn QA

As LinkedIn scales, it becomes crucial to identify and reduce flaky tests that intermittently fail. Your task is to implement a FlakyTestDetector that monitors test execution results and flags tests that exhibit flakiness.
- reportResult(testName: str, result: bool) -> None: Records the result of a test.
- isFlaky(testName: str) -> bool: Checks if a test is marked as flaky based on the number of reported results.
Example 1:
Input: reportResult('FeedTest', True)
Output: None
Explanation: Records a passing result for 'FeedTest'.
Example 2:
Input: isFlaky('FeedTest')
Output: False
Explanation: 'FeedTest' is not flaky since no failures recorded yet.
Constraints:
- 1 <= testName.length <= 50
- Each test can be reported multiple times.
coding Medium tree #2

2. [OA] Depth-First Search — Implement a Test Result Tracker for LinkedIn’s Automation Suite

LinkedIn needs to efficiently track and manage test results for its extensive automation suite. This involves navigating through a complex system of test cases and results.
You are tasked to implement a TestResultTracker class that can record and manage test outcomes efficiently.
- addResult(testName: str, result: bool) -> None: Records the result of a test case. If the test already exists, it updates the result.
- getResult(testName: str) -> bool: Retrieves the result of a test case, returning false if it doesn't exist.
Example 1:
Input: addResult('LoginTest', True)
Output: None
Explanation: Adds a test result for 'LoginTest'.
Example 2:
Input: getResult('LoginTest')
Output: True
Explanation: Returns the result for 'LoginTest'.
Constraints:
- 1 <= testName.length <= 100
- result is a boolean value (True or False).
system design Senior concurrency #3

3. [OA] Class Design — Design a Load Test Orchestrator for LinkedIn's Platform

As LinkedIn's infrastructure scales, it's essential to ensure the platform supports heavy loads. Your task is to create a LoadTestOrchestrator that manages various load test scenarios.
- addTestCase(testName: str, load: int) -> None: Adds a load test case with a specific load.
- runLoadTests() -> Dict[str, str]: Runs all added tests and returns their results.
Example 1:
Input: addTestCase('ProfilePage', 1000)
Output: None
Explanation: Adds a load test case for the Profile Page with a load of 1000 users.
Example 2:
Input: runLoadTests()
Output: {'ProfilePage': 'Passed'}
Explanation: Executes added load tests and returns their results.
Constraints:
- 1 <= testName.length <= 100
- Each test can handle 0 < load <= 10000.
system design Hard api design #4

4. [OA] Class Design — Design a Test Result Aggregator for LinkedIn QA Automation

In the context of LinkedIn's growing automation suite, you are tasked with creating a TestResultAggregator that encapsulates the management and reporting of test results across different suites.
- addTestResult(suiteName: str, testName: str, result: bool) -> None: Adds a result for a test under a specified suite.
- getSuiteResult(suiteName: str) -> float: Calculates and returns the pass rate of all tests in a given suite, as a percentage.
Example 1:
Input: addTestResult('UI', 'LoginTest', True)
Output: None
Explanation: Adds a passing result for the 'LoginTest' in the 'UI' suite.
Example 2:
Input: getSuiteResult('UI')
Output: 100.0
Explanation: The pass rate is 100% for the 'UI' suite since there’s one passing test.
Constraints:
- 1 <= suiteName.length <= 50
- Each suite can contain up to 1000 tests.

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