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Infosys Specialist Programmer (SP)

Complete Interview Question Bank (300+ Questions)

Target Package: ₹21 LPA | Role: Specialist Programmer / Power Programmer

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★ Latest 2026 Asked Questions (Real-time)

Based on recent interview experiences (Off-campus & On-campus)

Recent Coding Problems (LeetCode/GFG):
System Design & Concepts:
  1. Swap two numbers without using a third variable.
  2. Longest Common Subsequence (LCS) - Dynamic Programming.
  3. Write a program to print a spiral matrix.

I. Arrays & Strings

  1. Find the maximum sum subarray (Kadane's Algorithm)
  2. Find the missing number in an array of 1 to N
  3. Rotate an array by K positions (Right/Left)
  4. Find the duplicate number in an array of N+1 integers
  5. Merge two sorted arrays without extra space
  6. Find the longest consecutive sequence in an unsorted array
  7. Trapping Rain Water problem
  8. Next Permutation
  9. Longest Substring Without Repeating Characters
  10. Group Anagrams from a list of strings
  11. Minimum Window Substring
  12. Longest Palindromic Substring
  13. Product of Array Except Self
  14. Search in Rotated Sorted Array
  15. Container With Most Water
  16. 3Sum Problem (Find triplets with zero sum)
  17. Median of Two Sorted Arrays (Hard)
  18. Sort Colors (0s, 1s, 2s)
  19. First Missing Positive
  20. Subarray Sum Equals K
  21. Rearrange Array Alternately
  22. Count Pairs with Given Sum
  23. Row with Max 1s in a Boolean 2D Matrix
  24. Spiral Matrix Traversal
  25. Set Matrix Zeroes
  26. Majority Element (I & II)
  27. Gas Station (Greedy Circuit)
  28. Candy Problem (Hard Greedy)
  29. H-Index (I & II)
  30. Insert Delete GetRandom O(1)
  31. Minimum Size Subarray Sum
  32. Longest Repeating Character Replacement
  33. Find All Anagrams in a String
  34. Permutation in String (Sliding Window)
  35. Game of Life (In-place)
  36. Increasing Triplet Subsequence
  37. Summary Ranges

II. Searching & Sorting

  1. Binary Search (Iterative & Recursive)
  2. Search Insert Position
  3. Find First and Last Position of Element in Sorted Array
  4. Find Peak Element
  5. Kth Largest Element in an Array
  6. Merge Sort Implementation
  7. Quick Sort Implementation
  8. Count Inversions in an Array
  9. Allocate Minimum Pages (Binary Search on Answer)
  10. Aggressive Cows Problem

III. Linked Lists

  1. Reverse a Linked List (Iterative & Recursive)
  2. Detect Cycle in a Linked List (Floyd’s Cycle Finding)
  3. Find the intersection point of two Linked Lists
  4. Remove N-th node from end of list
  5. Merge K Sorted Lists
  6. Add two numbers represented by Linked Lists
  7. Palindrome Linked List check
  8. Flatten a Multilevel Doubly Linked List
  9. Reverse Nodes in k-Group
  10. Copy List with Random Pointer
  11. Rotate List
  12. Remove Duplicates from Sorted List II
  13. Partition List
  14. Sort List (Merge Sort on Linked List)
  15. Odd Even Linked List

IV. Stacks & Queues

  1. Implement Queue using Stacks
  2. Implement Stack using Queues
  3. Min Stack Implementation
  4. Next Greater Element
  5. Valid Parentheses (Balanced Brackets)
  6. Largest Rectangle in Histogram
  7. Sliding Window Maximum
  8. Stock Span Problem
  9. The Celebrity Problem
  10. Sort a Stack using Recursion
  11. Circular Queue Implementation
  12. Design a Double Ended Queue (Deque)
  13. Flatten Nested List Iterator
  14. Implement Stack using Array
  15. Check for redundant brackets
  16. Evaluate Reverse Polish Notation
  17. Basic Calculator (I & II)
  18. Daily Temperatures
  19. Remove K Digits
  20. Task Scheduler
  21. Design Circular Deque
  22. Asteroid Collision
  23. Trapping Rain Water (Stack Solution)
  24. Simplify Path (Canonical Path)

V. Trees (Binary Trees & BST)

  1. Maximum Depth of Binary Tree
  2. Check if two trees are identical
  3. Level Order Traversal (BFS)
  4. Zigzag Level Order Traversal
  5. Lowest Common Ancestor (LCA) in BST and Binary Tree
  6. Validate Binary Search Tree
  7. Diameter of Binary Tree
  8. Binary Tree Maximum Path Sum
  9. Serialize and Deserialize Binary Tree
  10. Symmetric Tree (Mirror Image)
  11. Balanced Binary Tree Check
  12. Path Sum III
  13. Construct Binary Tree from Preorder and Inorder
  14. Flatten Binary Tree to Linked List
  15. Burn a Tree (Minimum time to burn)
  16. Count Complete Tree Nodes
  17. Vertical Order Traversal
  18. Top View of Binary Tree
  19. Bottom View of Binary Tree
  20. Kth Smallest Element in BST
  21. Construct Binary Tree from Inorder and Postorder Traversal
  22. Populating Next Right Pointers in Each Node
  23. Convert Sorted Array to Binary Search Tree
  24. Path Sum (I, II, III)
  25. Sum Root to Leaf Numbers
  26. Binary Tree Right Side View
  27. Maximum Width of Binary Tree
  28. All Nodes Distance K in Binary Tree
  29. Lowest Common Ancestor of a Binary Search Tree
  30. Delete Node in a BST
  31. Trim a Binary Search Tree
  32. Range Sum of BST
  33. Convert BST to Greater Tree

VI. Graphs

  1. Number of Islands (Graph BFS/DFS)
  2. Rotting Oranges
  3. Course Schedule (Topological Sort)
  4. Word Ladder
  5. Graph Valid Tree
  6. Dijkstra's Algorithm (Shortest Path)
  7. Clone Graph
  8. Number of Provinces
  9. Surrounded Regions
  10. Course Schedule II (Order of courses)
  11. Alien Dictionary
  12. Prim’s Algorithm (MST)
  13. Kruskal’s Algorithm (MST)
  14. Bellman-Ford Algorithm
  15. Floyd Warshall Algorithm

VII. Greedy Algorithms

  1. Activity Selection Problem
  2. N Meetings in One Room
  3. Fractional Knapsack
  4. Minimum Platforms Required
  5. Job Sequencing Problem
  6. Huffman Coding
  7. Minimum Coins to make a value
  8. Lemonade Change
  9. Jump Game I
  10. Jump Game II (Minimum jumps)

VIII. Backtracking & Recursion

  1. N-Queens Problem
  2. Sudoku Solver
  3. M-Coloring Problem
  4. Rat in a Maze
  5. Word Search (Grid)
  6. Permutations of a String/Array
  7. Subsets (Power Set)
  8. Combination Sum
  9. Palindrome Partitioning
  10. Letter Combinations of a Phone Number
  11. Generate Parentheses
  12. Combination Sum (I, II, III)
  13. Permutations II (Unique)
  14. Subsets II (Duplicates)
  15. Restore IP Addresses
  16. Partition to K Equal Sum Subsets
  17. Beautiful Arrangement

IX. Dynamic Programming (High Priority)

  1. Climbing Stairs
  2. Coin Change Problem
  3. Longest Increasing Subsequence (LIS)
  4. Longest Common Subsequence (LCS)
  5. Edit Distance
  6. 0/1 Knapsack Problem
  7. Maximum Product Subarray
  8. Word Break Problem
  9. Partition Equal Subset Sum
  10. Matrix Chain Multiplication
  11. Minimum Path Sum (Grid)
  12. Unique Paths
  13. House Robber I
  14. House Robber II (Circular)
  15. Target Sum
  16. Unbounded Knapsack (Rod Cutting)
  17. Egg Dropping Puzzle
  18. Palindromic Partitioning
  19. Maximum Sum Increasing Subsequence
  20. Burst Balloons (Hard)

X. Bit Manipulation & Math

  1. Single Number (Find element appearing once)
  2. Check if a number is Power of Two
  3. Reverse Bits
  4. Count Set Bits (Kernighan’s Algo)
  5. Sieve of Eratosthenes (Prime Numbers)
  6. GCD and LCM (Euclidean Algo)
  7. Prime Factors of a Number
  8. Pascal's Triangle
  9. Divide Two Integers without operators
  10. Pow(x, n) - Binary Exponentiation

XI. Core Java & OOPs Concepts

  1. Explain the internal working of HashMap in Java. How are collisions handled?
  2. Difference between ArrayList and LinkedList. When to use which?
  3. What are the 4 pillars of OOPs? Explain with real-world examples.
  4. Explain Polymorphism (Compile-time vs Run-time).
  5. Difference between Abstract Class and Interface. Java 8 changes?
  6. What is the contract between equals() and hashCode()?
  7. Explain the Java Memory Model (Stack vs Heap).
  8. What is a Singleton Class? Write thread-safe Singleton code.
  9. Difference between 'final', 'finally', and 'finalize'.
  10. Explain Exception Handling hierarchy. Checked vs Unchecked exceptions.
  11. What is Garbage Collection? How does it work?
  12. Difference between String, StringBuilder, and StringBuffer.
  13. Explain Multi-threading in Java. Lifecycle of a Thread.
  14. What is Synchronization? Difference between synchronized method and block.
  15. What are Functional Interfaces and Lambda Expressions?
  16. Explain Stream API. Difference between map() and flatMap().
  17. What is Reflection API? Pros and Cons.
  18. Difference between Comparator and Comparable.
  19. What is the volatile keyword?
  20. Explain ClassLoaders in Java.
  21. What is the 'transient' keyword?
  22. Deep Copy vs Shallow Copy?
  23. Explain Design Patterns used in JDK (Factory, Observer, Decorator).
  24. Java 8 Stream API - filter vs map vs reduce.
  25. What is a Marker Interface?

XII. Database Management (DBMS) & SQL

  1. Explain ACID properties.
  2. Difference between Clustered and Non-Clustered Index.
  3. What is Normalization? Explain 1NF, 2NF, 3NF, BCNF.
  4. Difference between TRUNCATE, DELETE, and DROP.
  5. Explain different types of Joins (Inner, Left, Right, Full, Cross).
  6. Write a query to find the 2nd highest salary from the Employee table.
  7. Write a query to find duplicate records in a table.
  8. Difference between WHERE and HAVING clause.
  9. What are Stored Procedures and Triggers?
  10. What is a View? difference between View and Materialized View.
  11. Explain Indexing. How does it improve performance?
  12. What is a Primary Key vs Foreign Key vs Unique Key?
  13. Explain Deadlock. How to prevent it?
  14. SQL vs NoSQL databases. When to use which?
  15. Write a query to fetch the first 5 characters of a string.
  16. How to optimize a slow running query?
  17. Explain Sharding and Partitioning.
  18. What is a Cursor in SQL?
  19. Difference between UNION and UNION ALL.
  20. Write a query to calculate the number of employees in each department.
  21. Explain B-Tree vs B+ Tree.
  22. What is Database Replication?
  23. Explain CAP Theorem in context of NoSQL.
  24. Write a query to find Nth highest salary (Generic).
  25. Explain Inner vs Outer Join with Venn Diagram.

XIII. System Design (LLD & HLD)

  1. Design a URL Shortener (TinyURL).
  2. Design a Parking Lot System (LLD).
  3. Design an Elevator System (LLD).
  4. Design a Library Management System.
  5. Design WhatsApp/Chat Application (HLD).
  6. Explain Load Balancing. L4 vs L7 Load Balancers.
  7. What is Caching? Caching strategies (Write-through, Write-back).
  8. CAP Theorem explanation.
  9. Microservices vs Monolithic Architecture.
  10. How does HTTPS work? (SSL/TLS Handshake).
  11. Design an LRU Cache.
  12. Database Sharding strategies (Consistent Hashing).
  13. Design a Notification System.
  14. How to handle 1 Million requests per second?
  15. Design a Rate Limiter.
  16. Design Instagram / News Feed.
  17. Design a Chatbot.
  18. Design Typeahead Suggestion (Google Search).
  19. Design a Web Crawler.
  20. API Rate Limiting Algorithms (Token Bucket, Leaky Bucket).
  21. Design a Key-Value Store
  22. Design a Distributed Message Queue (Kafka)
  23. Design a File System
  24. Design Google Drive / Dropbox
  25. Design Uber / Lyft
  26. Design Tinder
  27. Design a Unique ID Generator (Snowflake)
  28. Design Ticketmaster
  29. Design Netflix / YouTube (Video Streaming)

XIV. Behavioral & HR Questions

  1. Tell me about yourself.
  2. Why Infosys? Why Specialist Programmer role?
  3. Describe a challenging project you worked on.
  4. How do you handle conflict with a team member?
  5. Tell me about a time you failed. What did you learn?
  6. Where do you see yourself in 5 years?
  7. Strengths and Weaknesses.
  8. Describe a time you showed leadership.
  9. How do you handle tight deadlines?
  10. Explain a complex technical concept to a non-technical person.

XV. Advanced Competitive Programming (Bonus)

  1. Segment Tree Implementation (Range Sum Query)
  2. Fenwick Tree (Binary Indexed Tree) Implementation
  3. Disjoint Set Union (DSU) with Path Compression & Rank
  4. KMP Algorithm (String Matching)
  5. Z-Algorithm for Pattern Matching
  6. Manacher's Algorithm (Longest Palindromic Substring O(n))
  7. Find Articulation Points and Bridges in a Graph
  8. Strongly Connected Components (Tarjan's or Kosaraju's Algo)
  9. Maximum Flow Problem (Ford-Fulkerson Algorithm)
  10. Convex Hull (Graham Scan Algorithm)

XVI. Additional Practice Topics (Quick Fire)

  • Operating Systems: Paging, Segmentation, Process Scheduling
  • Computer Networks: OSI Model, TCP vs UDP, DNS, HTTP Methods
  • Software Engineering: SDLC, Agile, Scrum, Waterfall
  • Testing: Unit Testing, Integration Testing, Mocking
  • Tools: Git, Docker, Jenkins, Maven/Gradle
  • Spring Boot: Annotations, Dependency Injection, IoC
  • REST APIs: Idempotency, Status Codes, API Design
  • Security: OWASP Top 10, SQL Injection, XSS
  • Cloud: AWS Basics (EC2, S3, RDS), Serverless
  • Design Patterns: Factory, Observer, Strategy, Builder

Good Luck! - BCVWorld Team