Why you should use Data Structures Test?

The Data Structures Test makes use of scenario-based questions to test for on-the-job skills as opposed to theoretical knowledge, ensuring that candidates who do well on this screening test have the relavant skills. The questions are designed to covered following on-the-job aspects: Ability to implement and work with Array data structures Knowledge of LinkedList data structure and its operations Proficiency in implementing and utilizing Stack data structure Understanding of Queue data structure and its applications Familiarity with Tree data structure and various traversal techniques Knowledge of Graph data structure and common algorithms like Dijkstra's and BFS Understanding and utilization of Hashing in solving data structure problems Proficiency in various sorting algorithms and their time complexities Knowledge of searching algorithms like binary search and their optimizations Understanding and application of recursion in solving problems

Data Structures Test

Q: What topics are covered in the Data Structures Test?

Array LinkedList Stack Queue Tree Graph Hashing Sorting Searching Recursion

About the test:

The Data Structures Test evaluates a candidate's understanding of fundamental data structures such as arrays, linked lists, stacks, queues, trees, and graphs. It assesses their knowledge of various data structures operations, algorithms, and problem-solving skills. The test includes multiple-choice questions to assess theoretical knowledge and coding questions to evaluate practical implementation.

Covered skills:

Array
Stack
Tree
Hashing
Searching

LinkedList
Queue
Graph
Sorting
Recursion

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9 reasons why

Adaface Data Structures Assessment Test is the most accurate way to shortlist Software Engineers

Reason #1

Tests for on-the-job skills

The Data Structures Test helps recruiters and hiring managers identify qualified candidates from a pool of resumes, and helps in taking objective hiring decisions. It reduces the administrative overhead of interviewing too many candidates and saves time by filtering out unqualified candidates at the first step of the hiring process.

The test screens for the following skills that hiring managers look for in candidates:

Ability to implement and manipulate arrays efficiently
Understanding and implementation of linked lists
Proficiency in stack operations and concepts
Ability to handle queue operations and understand its principles
Familiarity with tree data structures and its traversal techniques
Knowledge of graph data structure and its algorithms
Understanding of hashing techniques and its applications
Proficiency in sorting algorithms and their time complexities
Knowledge of searching techniques and their implementations
Understanding and application of recursion in problem-solving

Reason #2

No trick questions

Traditional assessment tools use trick questions and puzzles for the screening, which creates a lot of frustration among candidates about having to go through irrelevant screening assessments.

View sample questions

The main reason we started Adaface is that traditional pre-employment assessment platforms are not a fair way for companies to evaluate candidates. At Adaface, our mission is to help companies find great candidates by assessing on-the-job skills required for a role.

Why we started Adaface

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Reason #3

Non-googleable questions

We have a very high focus on the quality of questions that test for on-the-job skills. Every question is non-googleable and we have a very high bar for the level of subject matter experts we onboard to create these questions. We have crawlers to check if any of the questions are leaked online. If/ when a question gets leaked, we get an alert. We change the question for you & let you know.

How we design questions

These are just a small sample from our library of 10,000+ questions. The actual questions on this Data Structures Test will be non-googleable.

🧐 Question
Hard Graph Traversal and Data Storage Graph Theory Algorithm Analysis	Try practice test
Consider the following pseudo code implementing a specific graph traversal algorithm: What is the order in which the nodes are processed, and which data structure best represents the graph `G` for efficient traversal?
Medium Implementing a Browser's Back Button Stack Data Handling	Try practice test
You are tasked with implementing the "Back" button functionality in a web browser. This feature allows users to return to previously visited web pages in the order they were viewed. The browser maintains a history of URLs in a data structure. Considering the nature of web browsing, where users can go back multiple steps and then navigate to a new page (at which point the future history should be cleared), which data structure and algorithm would best implement this functionality? A: Use a heap, add the current URL when navigating to a new page, and remove the top element when the back button is used. B: Use a queue, enqueue the current URL when navigating to a new page, and dequeue when the back button is used. C: Use a single stack, push the current URL when navigating to a new page, and pop when the back button is used. D: Use an array, add the current URL to the end when navigating to a new page, and remove the last URL when the back button is used. E: Use a linked list, add the current URL to the head when navigating to a new page, and move backwards when the back button is used. F: Use two stacks, push the current URL to the first stack when navigating to a new page, and use the second stack to store the pages when the back button is used.
Easy Linked List Element Removal Linked Lists Element Removal	Try practice test
Consider a singly linked list where each node contains an integer value. Write a function `removeElement` that removes all occurrences of a specific value from the linked list. The function should return the head of the modified linked list. Pseudo code: What will be the content of the linked list referred to by `result` after executing the above pseudo code?
Easy Registration Queue Logic Queues	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
Medium Visitors Count Strings Logic	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

	🧐 Question	🔧 Skill
	Hard Graph Traversal and Data Storage Graph Theory Algorithm Analysis	3 mins Data Structures	Try practice test
Consider the following pseudo code implementing a specific graph traversal algorithm: What is the order in which the nodes are processed, and which data structure best represents the graph `G` for efficient traversal?
	Medium Implementing a Browser's Back Button Stack Data Handling	2 mins Data Structures	Try practice test
You are tasked with implementing the "Back" button functionality in a web browser. This feature allows users to return to previously visited web pages in the order they were viewed. The browser maintains a history of URLs in a data structure. Considering the nature of web browsing, where users can go back multiple steps and then navigate to a new page (at which point the future history should be cleared), which data structure and algorithm would best implement this functionality? A: Use a heap, add the current URL when navigating to a new page, and remove the top element when the back button is used. B: Use a queue, enqueue the current URL when navigating to a new page, and dequeue when the back button is used. C: Use a single stack, push the current URL when navigating to a new page, and pop when the back button is used. D: Use an array, add the current URL to the end when navigating to a new page, and remove the last URL when the back button is used. E: Use a linked list, add the current URL to the head when navigating to a new page, and move backwards when the back button is used. F: Use two stacks, push the current URL to the first stack when navigating to a new page, and use the second stack to store the pages when the back button is used.
	Easy Linked List Element Removal Linked Lists Element Removal	2 mins Data Structures	Try practice test
Consider a singly linked list where each node contains an integer value. Write a function `removeElement` that removes all occurrences of a specific value from the linked list. The function should return the head of the modified linked list. Pseudo code: What will be the content of the linked list referred to by `result` after executing the above pseudo code?
	Easy Registration Queue Logic Queues	30 mins Coding	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
	Medium Visitors Count Strings Logic	30 mins Coding	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

	🧐 Question	🔧 Skill	💪 Difficulty	⌛ Time
	Graph Traversal and Data Storage Graph Theory Algorithm Analysis	Data Structures	Hard	3 mins	Try practice test
Consider the following pseudo code implementing a specific graph traversal algorithm: What is the order in which the nodes are processed, and which data structure best represents the graph `G` for efficient traversal?
	Implementing a Browser's Back Button Stack Data Handling	Data Structures	Medium	2 mins	Try practice test
You are tasked with implementing the "Back" button functionality in a web browser. This feature allows users to return to previously visited web pages in the order they were viewed. The browser maintains a history of URLs in a data structure. Considering the nature of web browsing, where users can go back multiple steps and then navigate to a new page (at which point the future history should be cleared), which data structure and algorithm would best implement this functionality? A: Use a heap, add the current URL when navigating to a new page, and remove the top element when the back button is used. B: Use a queue, enqueue the current URL when navigating to a new page, and dequeue when the back button is used. C: Use a single stack, push the current URL when navigating to a new page, and pop when the back button is used. D: Use an array, add the current URL to the end when navigating to a new page, and remove the last URL when the back button is used. E: Use a linked list, add the current URL to the head when navigating to a new page, and move backwards when the back button is used. F: Use two stacks, push the current URL to the first stack when navigating to a new page, and use the second stack to store the pages when the back button is used.
	Linked List Element Removal Linked Lists Element Removal	Data Structures	Easy	2 mins	Try practice test
Consider a singly linked list where each node contains an integer value. Write a function `removeElement` that removes all occurrences of a specific value from the linked list. The function should return the head of the modified linked list. Pseudo code: What will be the content of the linked list referred to by `result` after executing the above pseudo code?
	Registration Queue Logic Queues	Coding	Easy	30 mins	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
	Visitors Count Strings Logic	Coding	Medium	30 mins	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

Reason #4

1200+ customers in 75 countries

With Adaface, we were able to optimise our initial screening process by upwards of 75%, freeing up precious time for both hiring managers and our talent acquisition team alike!

Brandon Lee, Head of People, Love, Bonito

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Reason #5

Designed for elimination, not selection

The most important thing while implementing the pre-employment Data Structures Test in your hiring process is that it is an elimination tool, not a selection tool. In other words: you want to use the test to eliminate the candidates who do poorly on the test, not to select the candidates who come out at the top. While they are super valuable, pre-employment tests do not paint the entire picture of a candidate’s abilities, knowledge, and motivations. Multiple easy questions are more predictive of a candidate's ability than fewer hard questions. Harder questions are often "trick" based questions, which do not provide any meaningful signal about the candidate's skillset.

Science behind Adaface tests

Reason #6

1 click candidate invites

Email invites: You can send candidates an email invite to the Data Structures Test from your dashboard by entering their email address.

Public link: You can create a public link for each test that you can share with candidates.

API or integrations: You can invite candidates directly from your ATS by using our pre-built integrations with popular ATS systems or building a custom integration with your in-house ATS.

Reason #7

Detailed scorecards & benchmarks

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Reason #8

High completion rate

Adaface tests are conversational, low-stress, and take just 25-40 mins to complete.

This is why Adaface has the highest test-completion rate (86%), which is more than 2x better than traditional assessments.

Reason #9

Advanced Proctoring

Learn more

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About the Data Structures Online Test

Why you should use Pre-employment Data Structures Test?

The Data Structures Test makes use of scenario-based questions to test for on-the-job skills as opposed to theoretical knowledge, ensuring that candidates who do well on this screening test have the relavant skills. The questions are designed to covered following on-the-job aspects:

Ability to implement and work with Array data structures
Knowledge of LinkedList data structure and its operations
Proficiency in implementing and utilizing Stack data structure
Understanding of Queue data structure and its applications
Familiarity with Tree data structure and various traversal techniques
Knowledge of Graph data structure and common algorithms like Dijkstra's and BFS
Understanding and utilization of Hashing in solving data structure problems
Proficiency in various sorting algorithms and their time complexities
Knowledge of searching algorithms like binary search and their optimizations
Understanding and application of recursion in solving problems

Once the test is sent to a candidate, the candidate receives a link in email to take the test. For each candidate, you will receive a detailed report with skills breakdown and benchmarks to shortlist the top candidates from your pool.

What topics are covered in the Data Structures Test?

Array
Array is a data structure that stores a fixed-size sequence of elements of the same type. It allows for efficient random access and modification of elements. The skill of working with arrays is measured in this test to evaluate the candidate's ability to manipulate and optimize data storage and retrieval using this fundamental data structure.
LinkedList
LinkedList is a data structure that consists of a series of nodes, each containing an element and a reference to the next node. It provides efficient insertion and deletion operations in comparison to arrays. This skill is assessed to gauge the candidate's understanding of dynamic memory allocation and their ability to implement and use linked lists for various applications.
Stack
Stack is an abstract data type that follows the Last-In-First-Out (LIFO) principle. It supports two primary operations: push, which adds an element to the top of the stack, and pop, which removes the topmost element. This skill is tested to assess the candidate's knowledge of stack-based algorithms and their ability to implement stack-based solutions for problems.
Queue
Queue is an abstract data type that follows the First-In-First-Out (FIFO) principle. It supports two primary operations: enqueue, which adds an element to the end of the queue, and dequeue, which removes the frontmost element. This skill is measured in the test to evaluate the candidate's familiarity with queue-based algorithms and their proficiency in implementing queue-based solutions for various problems.
Tree
Tree is a hierarchical data structure consisting of nodes connected by edges. It has a single root node and can have a varying number of child nodes. The skill of working with trees is assessed in this test to evaluate the candidate's ability to understand and implement tree-based algorithms like traversals, searching, and balancing.
Graph
Graph is a non-linear data structure composed of a set of nodes (vertices) and a set of edges that connect these nodes. It is used to represent relationships between objects and entities. Testing the skill of working with graphs helps measure candidates' understanding of graph algorithms like traversal, shortest path, and connectivity.
Hashing
Hashing is a technique that converts a given data item into a unique index value using a hash function. It allows for efficient retrieval and storage of data by minimizing the searching time. This skill is measured in the test to evaluate the candidate's ability to implement and use hash-based data structures, such as hash tables and hash maps.
Sorting
Sorting is the process of arranging elements in a specific order, such as ascending or descending. It is an important skill to assess as sorting algorithms are fundamental for various applications. Evaluating the candidate's proficiency in sorting algorithms helps determine their ability to efficiently organize data.
Searching
Searching is the process of finding a particular element(s) in a given collection of data. It is crucial for information retrieval and decision-making. Assessing the candidate's skill in searching algorithms helps identify their ability to locate and retrieve data efficiently across different data structures.
Recursion
Recursion is a programming technique where a function calls itself to solve a problem by breaking it into smaller sub-problems. It allows for elegant and concise code solutions but requires proper understanding and handling to avoid infinite loops. Testing the skill of recursion helps evaluate the candidate's ability to think recursively and solve complex problems efficiently.
Full list of covered topics
The actual topics of the questions in the final test will depend on your job description and requirements. However, here's a list of topics you can expect the questions for Data Structures Test to be based on.
Array insertion
Array deletion
Array searching
Array sorting
Linked list creation
Linked list traversal
Linked list insertion
Linked list deletion
Stack operations
Queue operations
Binary tree creation
Binary tree traversal
Binary tree insertion
Binary tree deletion
Graph representation
Graph traversal
Graph shortest path
Graph cycle detection
Hashing techniques
Hash functions
Hash table operations
Bubble sort
Selection sort
Insertion sort
Merge sort
Quick sort
Binary search
Linear search
Binary search tree creation
Binary search tree traversal
Binary search tree insertion
Binary search tree deletion
Recursion basics
Recursive algorithms
Recursive data structures
Recursive backtracking

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What roles can I use the Data Structures Test for?

Software Engineer
Data Analyst
Web Developer
Software Tester
Computer Programmer
IT Freshers

How is the Data Structures Test customized for senior candidates?

For intermediate/ experienced candidates, we customize the assessment questions to include advanced topics and increase the difficulty level of the questions. This might include adding questions on topics like

Ability to design and implement efficient algorithms with given requirements
Knowledge of complexity analysis and ability to optimize code for performance
Proficiency in implementing data structures using object-oriented principles
Understanding of memory management techniques and efficient memory usage
Familiarity with various types of trees like binary search trees and AVL trees
Knowledge of graph algorithms like topological sorting and minimum spanning trees
Ability to handle large datasets and efficiently process data
Understanding and utilization of dynamic programming in problem-solving
Proficiency in using various data structures to solve real-world problems
Knowledge of trade-offs between different data structures and their use cases

The coding question for experienced candidates will be of a higher difficulty level to evaluate more hands-on experience.

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The hiring managers felt that through the technical questions that they asked during the panel interviews, they were able to tell which candidates had better scores, and differentiated with those who did not score as well. They are highly satisfied with the quality of candidates shortlisted with the Adaface screening.

85%

reduction in screening time

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Data Structures Hiring Test FAQs

Can I combine multiple skills into one custom assessment?

Yes, absolutely. Custom assessments are set up based on your job description, and will include questions on all must-have skills you specify. Here's a quick guide on how you can request a custom test.

Do you have any anti-cheating or proctoring features in place?

We have the following anti-cheating features in place:

Non-googleable questions
IP proctoring
Screen proctoring
Web proctoring
Webcam proctoring
Plagiarism detection
Secure browser
Copy paste protection

Read more about the proctoring features.

How do I interpret test scores?

The primary thing to keep in mind is that an assessment is an elimination tool, not a selection tool. A skills assessment is optimized to help you eliminate candidates who are not technically qualified for the role, it is not optimized to help you find the best candidate for the role. So the ideal way to use an assessment is to decide a threshold score (typically 55%, we help you benchmark) and invite all candidates who score above the threshold for the next rounds of interview.

What experience level can I use this test for?

Each Adaface assessment is customized to your job description/ ideal candidate persona (our subject matter experts will pick the right questions for your assessment from our library of 10000+ questions). This assessment can be customized for any experience level.

Does every candidate get the same questions?

Yes, it makes it much easier for you to compare candidates. Options for MCQ questions and the order of questions are randomized. We have anti-cheating/ proctoring features in place. In our enterprise plan, we also have the option to create multiple versions of the same assessment with questions of similar difficulty levels.