Top 30 Data Structure Interview Questions for 2025

May 28, 2025

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Preparing for a tech interview can be intimidating—especially when you’re just starting out. One of the biggest hurdles? Data structures. They might seem abstract at first, but once you get the hang of them, they’re powerful tools that can make your code faster, cleaner, and more efficient.

If you're a fresher or early-career developer aiming for software roles, you’ve probably heard just how often interviewers test your understanding of arrays, stacks, trees, graphs, and more. These questions aren’t just meant to trip you up—they’re used to see how you think, solve problems, and write code that scales.

This blog brings together 30 important data structure questions you're likely to face in interviews. Each one is explained clearly, along with why it matters and how you can approach it with confidence. Let’s get started.

Overview of Data Structure  

Data structures are essential tools in computer science for organising and managing data efficiently. Key types include arrays, linked lists, stacks, queues, trees, graphs, heaps, and hash tables. Each has unique strengths that suit different types of problems and operations.

In interviews, you're tested on both theoretical knowledge and practical application of these structures. Expect questions on implementation, use cases, and performance trade-offs. Practicing problems regularly helps sharpen your problem-solving and optimization skills.

Still feeling confused? Connect with a mentor or tap into expert guidance to boost your clarity and confidence.

Now that you have a clear overview of data structures and their significance, it’s time to dive deeper. Here are the top 30 beginner to intermediate data structure interview questions and answers to help you prepare confidently and effectively.

Top 30 Data Structure Interview Questions for Freshers

1) What are data structures?

Significance:
This question checks your foundational understanding of data structures, which are essential for organizing, storing, and processing data efficiently.

Sample Answer:

Data structures are specialized formats used to organize, manage, and store data for efficient access and modification. Common types include arrays, linked lists, stacks, queues, trees, and graphs. Choosing the right data structure directly impacts an application's performance and scalability. They find extensive uses in database management, artificial intelligence, machine learning, operating systems, network routing, cybersecurity, gaming, data analytics, web development, and cloud computing.

2) What are the Applications of Data Structures?

Significance:

Data structures are the backbone of efficient software systems and are deeply integrated into countless real-world applications. Their role is crucial in organizing, accessing, and processing data optimally across domains.

Sample Answer:

  • Database Indexing: Structures like B-trees and tries are used to index and retrieve data quickly in relational and NoSQL databases.
  • Caching Mechanisms: LRU caches are implemented using a combination of hash maps and doubly linked lists to store frequently accessed data for fast retrieval.
  • Neural Network Graphs: Graph structures represent layers and connections in neural networks, allowing efficient computation and backpropagation in deep learning.
  • Genomic Sequence Matching: Tries and hash maps are used to store and quickly match DNA sequences in genome analysis and research.
  • Search and Recommendation Engines: Heaps and hash tables support fast data ranking and retrieval for personalized search results and content suggestions.
  • Pattern Recognition: Arrays and hash tables accelerate recognition tasks by enabling quick lookups in AI-based image and speech analysis.
  • Task Scheduling: Priority queues and heaps manage task execution order based on priority in operating systems and AI decision systems.
  • Data Compression: Trees, like Huffman trees, are used for encoding schemes to compress data efficiently in files and genetic information.
  • Network Routing: Graphs model networks and help compute the shortest or most efficient path for data transfer or genetic alignment.
  • Memory Management: Linked lists dynamically allocate and manage memory blocks in system-level programs and database engines.

3) What is the process of storing a variable in memory?

Significance:
This question tests your understanding of how variables are stored in memory, a key concept in programming and memory management.

Sample Answer:

Storing a variable in memory involves allocating a specific memory location to hold its value based on data type and scope. The following are key concepts.

  • Declaration: The variable is declared with a data type (e.g., int, float), which defines its size and behavior.
  • Memory Allocation: The compiler or runtime system assigns a memory address to store the variable.
  • Initialization: A value is assigned to the variable, which gets stored at the allocated address.
  • Symbol Table: The variable name is mapped to its memory location internally.
  • Scope & Lifetime: Determines how long the variable exists in memory and where it can be accessed from.

4) Clarify the difference between file structure and storage structure 

Significance:
This question helps distinguish between how data is organized at the user level (file structure) versus how it's managed physically in memory or disk (storage structure).

Sample Answer:

File structure and storage structure refer to different levels of data organization—logical vs. physical representation.

File Structure:

  • Refers to the logical organization of data in files.
  • Visible to users or programs, meant for ease of access and manipulation.
  • Common examples include text files, CSV, JSON, and binary files.
  • Its main purpose is to help users manage and access data in a human-readable or structured way.
  • Operates at a high level of abstraction.

🔹 Storage Structure:

  • Refers to the physical representation of data in memory or disk.
  • Managed by the system, typically invisible to end users.
  • Examples include arrays, linked lists, and hash tables.
  • Focused on how data is stored and retrieved efficiently by the system.
  • Operates at a low level, closer to hardware or memory architecture.

5) Which are the two major types of data structures?

Significance:

This question evaluates your awareness of the two main types of data structures and their roles in solving various computational problems efficiently.

Sample Answer:

  • Linear Data Structures: These store data sequentially, where elements are arranged one after another. Arrays use fixed-size indexing, while linked lists offer dynamic memory with pointer-linked nodes. Stacks (LIFO), queues (FIFO), and deques (insert/remove from both ends) manage data flow based on specific access rules.
  • Non-Linear Data Structures: These organize data hierarchically or through complex relationships. Trees (like BSTs, AVL, B-Trees, Tries) enable structured, sorted storage and quick access. Graphs connect data via nodes and edges, modeling networks, while heaps support efficient priority-based operations using a tree structure.

6) What is a stack?

Significance:
This question tests your understanding of the stack data structure, which is fundamental in algorithm design and system management.

Sample Answer:

A stack is a linear data structure that follows the Last In, First Out (LIFO) principle. It's used for managing function calls, expression evaluation, and backtracking problems. The main stack operations are as follows:

  • Push: Adds an element to the top of the stack.
  • Pop: Removes the top element from the stack.
  • Peek/Top: Returns the top element without removing it.
  • IsEmpty: Checks if the stack is empty.

7) What is a Queue? 

Significance:
This question assesses your knowledge of queues, which are essential for managing tasks in a first-come, first-served order, such as scheduling and buffering.

Sample Answer:

A queue is a linear data structure that follows the First In, First Out (FIFO) principle. It’s widely used for scheduling tasks and managing resource allocation. Common functions include the following.

  • Enqueue: Adds an element to the rear of the queue.
  • Dequeue: Removes the front element from the queue.
  • Front: Returns the front element without removing it.
  • IsEmpty: Checks if the queue is empty.

8) What is an Array? 

Significance:
This question evaluates your understanding of arrays, a fundamental data structure used for storing and accessing elements in a fixed-size, indexed format.

Sample Answer:

An array is a collection of elements stored in contiguous memory locations, where each element can be accessed using an index. Its main features are as follows.

  • Fixed Size: The size of an array is determined at the time of declaration.
  • Indexed Access: Elements can be accessed using an index, starting from 0.
  • Homogeneous: All elements in an array are of the same data type.
  • Static Allocation: Memory for arrays is allocated at compile time.

9) What is a Linked List?

Significance:

This question tests your knowledge of linked lists, which are crucial for dynamic memory allocation and efficient insertions or deletions.

Sample Answer:

A linked list is a linear data structure where elements, called nodes, are stored in memory with each node pointing to the next.

  • Node: Each element contains data and a reference (pointer) to the next node.
  • Dynamic Size: The size can grow or shrink dynamically during execution.
  • Insertion/Deletion: Efficient insertions and deletions compared to arrays, especially for large data.
  • Singly Linked List: Each node points to the next node in one direction.
  • Doubly Linked List: Each node has pointers to both the next and previous nodes.

10) Differentiate between Stack and Queue Data Structure

Significance:
This question tests your understanding of the core differences between two fundamental linear data structures—stack and queue—and how they manage data.

Sample Answer:

A stack follows the Last In, First Out (LIFO) principle, while a queue works on First In, First Out (FIFO). 

🔹 Stack:

  • Follows the LIFO (Last In, First Out) principle.
  • Insertion and deletion happen at the same end — the top.
  • Common operations include:
    • Push: Add an element to the top.
    • Pop: Remove the top element.
    • Peek: View the top element without removing it.
  • Use cases: Managing function calls, undo features in editors, backtracking algorithms, expression evaluation.

🔹 Queue:

  • Follows the FIFO (First In, First Out) principle.
  • Insertion occurs at the rear, and deletion at the front.
  • Common operations include:
    • Enqueue: Add an element at the rear.
    • Dequeue: Remove the element from the front.
    • Front: View the front element without removing it.
  • Use cases: Task scheduling, handling requests in servers, print spooling, buffering in streaming services.

11) What is a Binary Search Tree?

Significance:
This question checks your understanding of binary search trees (BSTs), which are crucial for efficient searching, insertion, and deletion operations.

Sample Answer:

Figure 1. Binary Search Tree

A Binary Search Tree is a type of binary tree where each node has at most two children, and values are organized to allow for fast lookup.

  • Left Subtree: Contains nodes with values less than the parent node.
  • Right Subtree: Contains nodes with values greater than the parent node.
  • Search Efficiency: Offers average-case time complexity of O(log n) for search, insert, and delete operations.
  • No Duplicates: Typically, BSTs do not allow duplicate values.
  • Applications: Used in database indexing, expression parsing, and dynamic sorting.

12) How does Binary Search differ from Linear Search?

Significance:
This question checks your grasp of basic search algorithms and how their efficiency varies depending on the data and use case.

Sample Answer:

Binary search and linear search are two fundamental algorithms for finding elements, differing mainly in speed and data requirements.

Feature Linear Search Binary Search
Data Requirement Works on unsorted or sorted data Requires data to be sorted
Approach Scans each element one by one Repeatedly divides the search interval in half
Time Complexity O(n) O(log n)
Best Case First element is the target Middle element is the target
Use Case Small or unsorted datasets Large, sorted datasets
Efficiency Less efficient for large datasets More efficient, but needs sorted input

13) What are Tree traversals? 

Significance:
This question tests your knowledge of tree traversal techniques, which are essential for visiting and processing all nodes in a tree data structure.

Sample Answer:

Tree traversal refers to the process of visiting all nodes in a tree, usually in a specific order to solve various problems like searching or printing.

  • In-order Traversal: Visit the left subtree, the root, and then the right subtree. Produces sorted output for binary search trees.
  • Pre-order Traversal: Visit the root first, then the left subtree, followed by the right subtree. Useful for copying trees.
  • Post-order Traversal: Visit the left subtree, the right subtree, and then the root. Used for tree deletion or evaluating expressions.
  • Level-order Traversal: Visit nodes level by level from top to bottom, using a queue. Common for breadth-first search.

For the binary search tree in Figure 1 above, the tree traversals are as follows:

Inorder:   1 → 3 → 4 → 6 → 7 → 8 → 10 → 13 → 14  

Preorder:  8 → 3 → 1 → 6 → 4 → 7 → 10 → 14 → 13  

Postorder: 1 → 4 → 7 → 6 → 3 → 13 → 14 → 10 → 8  

Levelorder:8 → 3 → 10 → 1 → 6 → 14 → 4 → 7 → 13 

14) What is a Deque Data Structure? 

Significance:
This question checks your understanding of deques, a versatile data structure that supports efficient insertion and removal from both ends.

Sample Answer:

A deque (double-ended queue) is a linear data structure that allows insertion and removal of elements from both ends efficiently.

  • Insertion/Deletion: Elements can be added or removed from both the front and the rear.
  • Types of Deques:
    • Input-restricted Deque: Only allows insertion at the rear and removal from both ends.
    • Output-restricted Deque: Only allows insertion at the front and removal from both ends.
    • Fully-restricted Deque: Allows insertion and removal from both ends freely.
  • Time Complexity: O(1) for both insertions and deletions at either end.
  • Applications: Used in algorithms for sliding windows, task scheduling, and undo operations.

15) What is a Priority Queue?

Significance:
This question evaluates your understanding of priority queues, a specialized queue that ensures elements are processed based on priority rather than the order of arrival.

Sample Answer (Priority Queue and Its Applications):

A priority queue is a data structure where each element is associated with a priority, and elements are dequeued based on priority rather than the order of insertion.

  • Insertion: Elements are inserted with a priority value, and the queue maintains order according to priority.
  • Dequeue: The element with the highest (or lowest) priority is removed first, not necessarily the one inserted earliest.
  • Implementation: Typically implemented using heaps, which allow efficient priority-based operations.
  • Applications:
    • Scheduling: Task scheduling in operating systems (e.g., CPU scheduling).
    • Dijkstra’s Algorithm: Used in finding the shortest path in graphs.
    • Huffman Coding: For data compression algorithms.
    • Event Simulation: In simulations requiring events to be processed based on time or priority.

Are you struggling with the technical jargon? If the explanations feel too complex, let us know. Our top experts are here to simplify them so that you can nail your interview with confidence!

16) What is a Graph Data Structure? 

Significance:
This question tests your understanding of graphs, which are essential for modeling complex relationships in a variety of applications such as social networks and routing algorithms.

Sample Answer:

A graph is a collection of nodes (vertices) connected by edges (links), used to represent relationships between pairs of objects.

  • Vertices: The individual elements or nodes in the graph, which represent entities.
  • Edges: The connections between vertices, which represent relationships.
  • Directed Graph: Edges have a direction, i.e., they point from one vertex to another.
  • Undirected Graph: Edges have no direction, representing a bidirectional relationship.
  • Weighted Graph: Edges have weights representing costs or distances between vertices.
  • Applications: Used in networking, social networks, recommendation systems, and algorithms like shortest path (Dijkstra’s) and network flow.

17) What is an Adjacency Matrix? 

Significance:
This question tests your understanding of the adjacency matrix, a common representation of graphs, especially useful for dense graphs.

Sample Answer:

An adjacency matrix is a 2D array used to represent a graph, where each element indicates whether there is an edge between two vertices.

  • Matrix Representation: A square matrix where rows and columns represent vertices; a 1 indicates an edge, and a 0 means no edge.
  • Directed Graph: For a directed graph, if there is an edge from vertex i to vertex j, the matrix entry at [i][j] is 1.
  • Undirected Graph: For undirected graphs, the matrix is symmetric—[i][j] = [j][i].
  • Space Complexity: O(V²), where V is the number of vertices, making it inefficient for sparse graphs.
  • Applications: Useful in algorithms like depth-first search (DFS) and breadth-first search (BFS), especially when working with dense graphs.

18) What is the difference between breadth first and depth-first search? 

Significance:
This question tests your understanding of two fundamental graph traversal algorithms: breadth-first search (BFS) and depth-first search (DFS), each of which has different use cases and performance characteristics.

Sample Answer:

Breadth-first search (BFS) and depth-first search (DFS) are two graph traversal algorithms, differing in how they explore nodes.

🔹 Breadth-First Search (BFS):

  • Traversal style: Explores all nodes level-by-level (layer-wise).
  • Data structure used: Queue (FIFO).
  • Time complexity: O(V + E), where V = number of vertices, E = number of edges.
  • Space complexity: O(V) due to the queue storing all nodes at the current level.
  • Use cases:
    • Finding the shortest path in unweighted graphs.
    • Web crawling, level-order traversal in trees.
    • Broadcasting in networks.

🔹 Depth-First Search (DFS):

  • Traversal style: Explores as deeply as possible along each branch before backtracking.
  • Data structure used: Stack (LIFO) or recursion.
  • Time complexity: O(V + E).
  • Space complexity: O(V) due to recursive stack or explicit stack.
  • Use cases:
    • Cycle detection, topological sorting.
    • Solving mazes or puzzles.
    • Pathfinding where you need to explore all possible paths.

19) What is AVL Data Structure? 

Significance:
This question tests your knowledge of AVL trees, a type of self-balancing binary search tree that ensures efficient search, insertion, and deletion operations.

Sample Answer:

An AVL (Adelson-Velsky and Landis) tree is a self-balancing binary search tree where the heights of two child subtrees of any node differ by no more than one.

  • Balancing Factor: The balance factor is calculated as the height difference between the left and right subtrees. It should be between -1 and 1 for the tree to be balanced.
  • Rotations: When the tree becomes unbalanced, rotations (left, right, or double rotations) are used to restore balance.
  • Time Complexity: O(log n) for search, insertion, and deletion, ensuring efficient operations even in large datasets.
  • Applications: Used in applications requiring sorted data with fast updates, such as databases and file systems.
  • Advantages: Guarantees balanced height, avoiding the worst-case O(n) performance seen in regular binary search trees.

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20) What is Hashing? 

Significance:
This question tests your grasp of hashing, a fundamental technique used for fast data retrieval, especially in large datasets and real-time systems.

Sample Answer:

Hashing is a technique that maps data to a fixed-size value (hash code) using a hash function for quick data access.

  • Hash Function: Converts input data (key) into a specific index in a hash table.
  • Hash Table: A data structure that stores key-value pairs using hashed keys.
  • Collision Handling: Techniques like chaining and open addressing handle cases where multiple keys map to the same index.
  • Time Complexity: Offers average-case O(1) time for search, insert, and delete.

21) What is HashMap Data Structure? 

Significance:
This question tests your understanding of hash maps, a highly efficient data structure for key-value pair storage and fast lookups.

Sample Answer:

A HashMap is a data structure that stores data in key-value pairs and uses a hash function to map keys to specific indices.

  • Hash Function: Maps keys to unique indices in a hash table for quick lookup.
  • Key-Value Pair: Each value is accessed using a unique key, allowing for fast retrieval.
  • Collision Handling: Techniques like chaining or open addressing resolve cases when multiple keys map to the same index.
  • Time Complexity: O(1) for average-case insertions, deletions, and lookups.
  • Applications: Used in caching, databases, and maintaining unique elements in sets.

22) How are collisions handled by HashMap? 

Significance:
This question checks your understanding of how hash maps efficiently handle situations where multiple keys hash to the same index, ensuring optimal performance.

Sample Answer:

Collisions occur in hash maps when two different keys hash to the same index. These are managed using techniques like chaining or open addressing.

  • Chaining: Each hash table index stores a linked list (or another data structure) of elements that hash to the same index.
  • Open Addressing: When a collision occurs, the algorithm searches for the next available slot within the table (e.g., linear probing, quadratic probing).
  • Load Factor: To reduce collisions, the hash map resizes when the number of elements exceeds a certain threshold.
  • Rehashing: The table is resized, and all keys are rehashed to distribute them more evenly across the table.

23) What is Heap? 

Significance:
This question evaluates your understanding of heaps, which are essential in implementing priority queues and optimizing sorting and scheduling tasks.

Sample Answer:

A heap is a special tree-based data structure that satisfies the heap property and is commonly used for priority-based operations.

  • Heap Property: In a max-heap, the parent is greater than or equal to its children; in a min-heap, it’s the opposite.
  • Complete Binary Tree: A heap is always a complete binary tree, meaning all levels are fully filled except possibly the last.
  • Insertion/Deletion: Performed efficiently with heapify operations in O(log n) time.
  • Types: Includes Min-Heap and Max-Heap based on value arrangement.

24) What is Asymptotic Analysis? 

Significance:
This question tests your understanding of how to evaluate algorithm performance without running the code, which is key in writing efficient programs.

Sample Answer:

Asymptotic analysis evaluates the efficiency of an algorithm by measuring its running time or space as input size grows.

  • Big O (O): Describes the upper bound or worst-case time complexity.
  • Big Omega (Ω): Represents the lower bound or best-case performance.
  • Big Theta (Θ): Gives the tight bound—average-case or exact performance.
  • Focus: Ignores constants and lower-order terms to highlight scalability.

25) How to perform Quick Sort?

Significance:
This question assesses your understanding of the Quick Sort algorithm, which is one of the most efficient sorting algorithms for large datasets.

Sample Answer:

Quick Sort is a divide-and-conquer algorithm that sorts elements by partitioning the array into smaller sub-arrays based on a pivot.

  • Partitioning: Selects a pivot element and rearranges the array such that elements smaller than the pivot come before it, and larger ones after.
  • Recursion: Recursively applies the partitioning process to the sub-arrays.
  • Time Complexity: Average-case O(n log n), worst-case O(n²) when the pivot is poorly chosen.
  • Space Complexity: O(log n) for the recursive stack.
  • Applications: Used in database indexing, searching, and large-scale data processing due to its efficiency.

26) How to perform Merge Sort?

Significance:
This question tests your understanding of Merge Sort, a classic divide-and-conquer algorithm known for its predictable performance and stability.

Sample Answer:

Merge Sort is a divide-and-conquer sorting algorithm that recursively splits the array, sorts the halves, and then merges them.

  • Divide Step: The array is divided into two halves until each sub-array has a single element.
  • Conquer Step: Each pair of sub-arrays is merged in sorted order to build up a fully sorted array.
  • Time Complexity: O(n log n) in all cases (best, average, worst).
  • Space Complexity: O(n) due to the use of temporary arrays during merging.
  • Stable Sort: Maintains the relative order of equal elements.
  • Applications: Suitable for large datasets and external sorting (e.g., sorting data stored on disk).

27) What is B Tree and its Applications? 

Significance:
This question evaluates your understanding of B-Trees, which are essential for organizing and accessing large blocks of data efficiently in databases and filesystems.

Sample Answer:

A B-Tree is a self-balancing, multi-level search tree that maintains sorted data and allows efficient insertion, deletion, and search operations.

  • Multi-way Tree: Unlike binary trees, nodes can have more than two children (defined by order m).
  • Balanced Structure: Keeps all leaf nodes at the same depth, ensuring consistent access times.
  • Efficient Operations: Search, insert, and delete operations all run in O(log n) time.
  • Minimized Disk Reads: Designed to minimize disk I/O by storing large blocks of keys in a single node.
  • Applications:
    • Databases: Used in indexing large datasets for fast retrieval.
    • File Systems: Organize directory structures (e.g., NTFS, HFS+).
    • Search Engines: Store and manage huge volumes of indexed data.

28) Define Trie data structure and its applications. 

Significance:
This question tests your understanding of Tries, a specialized tree-based data structure used for efficient retrieval of strings, particularly in dictionary-based applications.

Sample Answer:

A Trie (pronounced "try") is a prefix tree used to store a dynamic set of strings where common prefixes are shared among branches.

  • Node Structure: Each node represents a character; paths from root to leaves form stored words.
  • Efficient Search: Enables fast lookups, insertions, and deletions, especially in scenarios involving large collections of strings.
  • No Duplicates: Naturally prevents duplicate entries and supports prefix matching efficiently.
  • Time Complexity: O(L), where L is the length of the word, for insert and search operations.
  • Applications:
    • Autocomplete: Suggests words based on input prefixes.
    • Spell Checkers: Validates words efficiently.
    • IP Routing: Matches prefixes in networking.
    • Dictionary Implementations: Fast word lookups in text editors or search engines

29) What is a Red-Black Tree & its Applications? 

Significance:
This question assesses your knowledge of Red-Black Trees, a type of self-balancing binary search tree used to maintain sorted data with guaranteed time complexities.

Sample Answer:

A Red-Black Tree is a self-balancing binary search tree where each node has an extra color bit (red or black) to ensure balance during insertions and deletions.

  • Balance Rules: No two red nodes appear consecutively, and every path from root to leaf has the same number of black nodes.
  • Height Balance: Ensures the longest path is no more than twice as long as the shortest, maintaining O(log n) operations.
  • Efficient Operations: Insert, delete, and search all operate in O(log n) time.
  • Color Rebalancing: Rotations and recoloring maintain tree balance after updates.
  • Applications:
    • Java TreeMap/TreeSet: Internally implemented using Red-Black Trees.
    • Linux Process Scheduler: Manages task scheduling in kernel using red-black trees.
    • Databases: Used for indexing and range queries.
    • Memory Management: Handles allocation tracking efficiently in compilers and OS kernels.

30) What’s the difference between Max-heap and  Min-heap 

Significance:
This question helps interviewers evaluate your understanding of heap variants and how they differ in maintaining priority in data.

Sample Answer:

Heaps are complete binary trees used to implement priority queues. The key difference lies in how the root relates to its children.

🔹 Max-Heap:

  • The root node contains the maximum element in the heap.
  • Each parent node is greater than or equal to its child nodes.
  • Use case: Ideal for applications needing quick access to the largest value, such as:
    • Implementing priority queues.
    • Performing heap sort (to sort in ascending order).
    • Job scheduling where highest priority tasks must be addressed first.

🔹 Min-Heap:

  • The root node contains the minimum element in the heap.
  • Each parent node is less than or equal to its child nodes.
  • Use case: Best suited for situations requiring the smallest value quickly, such as:
    • Shortest path algorithms like Dijkstra's.
    • Prim's algorithm for Minimum Spanning Tree (MST).
    • Task scheduling with earliest deadlines first.

🔹 Common Properties for Both:

  • Both are implemented as complete binary trees.
  • Insertion and deletion: O(log n) due to re-heapifying.
  • Accessing root element (max or min): O(1) time.

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Conclusion 

Preparing for tech interviews isn’t just about memorizing answers—it’s about building the confidence to tackle problems logically and efficiently. The data structure interview questions for freshers we covered in this blog are some of the most commonly asked and most impactful for entry-level roles. Understanding how and when to apply these concepts can make all the difference during a technical round.

As you keep practicing, remember: it’s not about getting every answer perfect the first time—it’s about improving your thought process and learning how to approach new challenges.

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