12 Essential Data Structures Interview Questions and Answers to Know

The editors at Solutions Review highlight the essential data structures interview questions and answers to know.

Data structures are the organization, management, and storage format that enables access and modification in the field of computer science. Data structures act as a collection of data values, the relationships among them, and the functions that can be applied to data. There are generally considered to be four kinds of data structures: linear (arrays and lists), tree (binary and heaps), hash, and graphs (decision or directed).

With this in mind, we’ve compiled this list of essential data structures interview questions and answers to save you time and help you ace your next interview. We compiled this resource by curating the most popular results from community forums like Quora and Reddit. Prospective data management leaders may also want to consult our directory of data engineering professional certifications as well.

Data Structures Interview Questions

Q: What are data structures?

A: Data structures are a specific way of organizing data in a computer so that it may be used for information gathering. Data structures also take into account the relationship between data.

Q: Where are data structures applied?

A: Data structures are applied in the following areas:

• Operating systems
• Compiler designs
• Simulations
• Graphics
• Numerical analysis
• Artificial intelligence
• Statistical analysis packages
• Database management systems

Q: What methods are used to store sequential files?

A: Sequential files are stored using the following methods:

• Natural merging
• Distribution of initial runs
• Straight merging
• Polyphase sort

Q: What is a spanning tree?

A: Spanning trees are trees associated with a network where all nodes of a graph are seen on the tree at once. A spanning tree must be organized via complete edge weight between nodes.

Q: What is a quick sort?

A: Quick sort algorithms follow the divide and conquer rule and works by decreasing a sort problem into many sorting problems, then solving for each problem. The dividing value is selected from input data and data is divided into three sets:

• Elements belonging to the value before dividing
• Elements that occur after dividing the value
• The value itself

Q: What is a merge sort?

A: Merge sort also follows the divide and conquer rule. It works with respect to data to be sorted as already-sorted lists. Sorted lists which are adjacent are combined into larger sorted lists until there is one sorted list that contains all elements. Merge sort effectively sorts all the lists and data structures that are not present in arrays.

Q: How do you search for data in a linked list?

A: The only way to search for data in a linked list is using linear search. Sometimes it is easy and fast to take data from a linked list and it is stored in the different data structures to make search more effective.

Q: When does a memory leak occur?

A: A memory leak may occur when a program loses the ability to free block memory that is allocated dynamically.

Q: What is precision?

A: Precision is the accuracy for the decimal part of a value. Precision is nothing but the number of digits permitted after a decimal point.

Q: What is the impact of signed numbers on memory?

A: The first bit in the storage allocated for a particular number has signed for that number. So to store a number, one bit will be less.

Q: How do you reverse memory using a declaration statement?

The data type is used to reverse memory in variable declaration. In the implementation of programming languages, there are predefined sizes for data types as well.

Q: How many parts are there in a declaration statement?

A: In a declaration statement, there are two parts and an optional third:

• Data type
• Variable identifier
• Optional third part: Qualifier type