SWE Fundamentals Part 1

Question 2

What is Big-O notation used for?

Answer 2

To describe the time and space complexity of an algorithm in terms of input size.

Question 3

What is the time complexity of accessing an array element?

Answer 3

O(1)

Question 4

What is the time complexity of searching in a hash table?

Answer 4

Average O(1), Worst O(n)

Question 5

What is the time complexity of binary search?

Answer 5

O(log n)

Question 6

What data structure is best for LIFO operations?

Answer 6

Stack

Question 7

What data structure is best for FIFO operations?

Answer 7

Queue

Question 8

What is the difference between a linked list and an array?

Answer 8

Linked lists are dynamic in size and better at insertions/deletions; arrays are faster for random access.

Question 9

When would you use a hash map?

Answer 9

When you need fast key-value lookups.

Question 10

What is recursion?

Answer 10

A function that calls itself to solve a smaller version of the problem.

Question 11

What is a base case in recursion?

Answer 11

The condition under which the recursive calls stop.

Question 12

What is the difference between DFS and BFS?

Answer 12

DFS explores depth before backtracking, BFS explores neighbors level by level.

Question 13

When should you use BFS over DFS?

Answer 13

When looking for the shortest path in an unweighted graph.

Question 14

What is dynamic programming?

Answer 14

An optimization technique for solving problems by storing and reusing subproblem results.

Question 15

What are the two main techniques in dynamic programming?

Answer 15

Memoization (top-down) and tabulation (bottom-up)

Question 16

What is a greedy algorithm?

Answer 16

An algorithm that chooses the best option at each step hoping to find a global optimum.

Question 17

What is a heap used for?

Answer 17

Efficiently getting the min or max element, often in priority queues.

Question 18

What is a graph?

Answer 18

A set of nodes (vertices) connected by edges.

Question 19

How is a graph represented in code?

Answer 19

Adjacency list or adjacency matrix

Question 20

What is selection sort’s time complexity?

Answer 20

O(n²) for all cases

Question 21

Why is bubble sort inefficient?

Answer 21

It makes many unnecessary swaps, leading to O(n²) performance.

Question 22

What is merge sort’s time complexity?

Answer 22

O(n log n)

Question 23

What is quicksort’s average and worst-case time complexity?

Answer 23

Average O(n log n), Worst O(n²)

Question 24

What is the stack used for in recursion?

Answer 24

To store function calls and local variables.

Question 25

What is the heap in memory?

Answer 25

A region for dynamically allocated memory (e.g., objects).

Question 26

What is garbage collection?

Answer 26

Automatic memory management that reclaims unused memory.

Question 27

What is reference counting in garbage collection?

Answer 27

Each object has a count of references; it's freed when the count is zero.

Question 28

What is mark-and-sweep garbage collection?

Answer 28

Live objects are marked, and unreachable ones are collected.

Question 29

What is generational garbage collection?

Answer 29

Objects are grouped by age; young ones are collected more frequently.

Question 30

What is the difference between stack and heap memory?

Answer 30

Stack is for static memory (function calls), heap is for dynamic memory (objects).

Question 31

What does “pass by value” mean?

Answer 31

The function gets a copy of the data, not the original.

Question 32

What is encapsulation in OOP?

Answer 32

Hiding internal state and requiring all access through methods.

Question 33

What is inheritance in OOP?

Answer 33

One class can inherit attributes and behavior from another.

Question 34

What is polymorphism in OOP?

Answer 34

Functions or methods behaving differently based on context or data types.

Question 35

What is a REST API?

Answer 35

An interface for communication between systems using HTTP methods like GET, POST, PUT, DELETE.

Question 36

What does HTTP status 200 mean?

Answer 36

Request was successful.

Question 37

What does HTTP status 404 mean?

Answer 37

Resource not found.

Question 38

What is Git used for?

Answer 38

Version control – tracking code changes over time.

Question 39

What is a Git branch?

Answer 39

A separate line of development in your codebase.

Question 40

How do you resolve a merge conflict?

Answer 40

Manually edit conflicting files and commit the resolution.

Question 41

What is unit testing?

Answer 41

Testing individual units of code (like functions or classes) for correctness.

Question 42

What is the call stack?

Answer 42

A data structure that stores information about active function calls.

Question 43

What is a “memory leak”?

Answer 43

When memory is allocated but never freed, causing usage to grow over time.

Question 44

What is the STAR method for behavioral questions?

Answer 44

Situation, Task, Action, Result – structure for clear answers.

Question 45

How should you answer “Tell me about yourself”?

Answer 45

Brief summary of your background, skills, and what you're looking for.

Question 46

How should you prepare for technical interviews?

Answer 46

Practice DSA problems, understand time/space complexity, and write code by hand.

Question 47

What should you talk about in a project interview question?

Answer 47

Problem, your role, technologies used, challenges faced, and what you learned.

Question 48

What is SQL?

Answer 48

A language used to query and manage relational databases.

Question 49

What does SELECT do in SQL?

Answer 49

Retrieves data from one or more tables.

Question 50

What is a primary key in a database?

Answer 50

A unique identifier for each row in a table.

Question 51

What is the difference between frontend and backend development?

Answer 51

Frontend is the user interface; backend is the logic and database interaction.

Question 52

What is the software development lifecycle (SDLC)?

Answer 52

The process of planning, building, testing, and deploying software.

Question 53

What is Agile?

Answer 53

A software development methodology focused on iterative progress and flexibility.

Question 54

What is CI/CD?

Answer 54

Continuous Integration and Continuous Deployment – automating build, test, and deployment workflows.

Question 55

What is a deployment pipeline?

Answer 55

A set of automated steps that deliver code changes from development to production.

Question 56

What is the difference between a bug and a feature request?

Answer 56

A bug is unintended broken behavior; a feature request is a new or improved functionality.

Question 57

What is a pull request (PR)?

Answer 57

A request to merge changes into the main codebase, usually reviewed by peers.

Question 58

What is code review?

Answer 58

Peer feedback on a pull request to ensure code quality and correctness.

Question 59

What is API rate limiting?

Answer 59

Controlling how often someone can make requests to an API within a time period.