Mastering DSA for Indian Tech Giants

Essential data structures and algorithms topics for FAANG and top Indian company interviews.

Key Statistics

  • 200-300 DSA problems typically solved by successful candidates
  • 45-60 minutes average time per coding interview round
  • Arrays, Strings, Trees cover 60% of interview questions
  • ₹20-50 LPA typical package at product-based companies for strong DSA skills

Essential Data Structures

Master these data structures before moving to complex algorithms.

1. Arrays & Strings

The foundation of DSA. Most interview questions start here.

  • Two-pointer technique for sorted arrays
  • Sliding window for subarray problems
  • Hash maps for frequency counting and lookups
  • String manipulation: palindrome, anagram, substring

2. Linked Lists

Test your pointer manipulation and memory management skills.

  • Reverse a linked list (iterative and recursive)
  • Detect and remove cycles (Floyd's algorithm)
  • Find middle node and nth node from end
  • Merge two sorted linked lists

3. Stacks & Queues

Essential for problems involving order and nested structures.

  • Valid parentheses and expression evaluation
  • Implement queue using stacks and vice versa
  • Next greater element problems
  • Monotonic stack for range queries

4. Trees & Graphs

The most important category for top-tier companies.

  • Tree traversals: inorder, preorder, postorder, level-order
  • BST operations: search, insert, delete, validate
  • Graph traversals: BFS, DFS with visited tracking
  • Shortest path: Dijkstra, BFS for unweighted graphs

Core Algorithms

Must-Know Algorithms

  • • Sorting: Merge sort, Quick sort (understand implementations)
  • • Searching: Binary search on arrays and answer spaces
  • • Recursion: Backtracking, divide and conquer
  • • Dynamic Programming: Memoization, tabulation, classic patterns
  • • Greedy: Activity selection, interval scheduling
  • • Hashing: Collision handling, load factor

Study Plan & Resources

Phase 1: Basics (1-2 months)

  • • Complete arrays, strings, and basic math
  • • Learn one language deeply (C++, Java, or Python)
  • • Solve 50 easy problems on LeetCode
  • • Understand time and space complexity (Big O)

Phase 2: Intermediate (2-3 months)

  • • Master linked lists, stacks, queues, trees
  • • Learn recursion and backtracking
  • • Solve 100 medium problems
  • • Start DP with classic problems (fibonacci, knapsack)

Phase 3: Advanced (2-3 months)

  • • Graphs, advanced DP, advanced trees
  • • Solve 50 hard problems
  • • Practice company-specific questions
  • • Mock interviews and timed practice

Recommended Resources

  • • LeetCode - 300+ problems with company tags
  • • GeeksforGeeks - Comprehensive tutorials and practice
  • • NeetCode.io - Structured roadmap with 150 problems
  • • Striver's DSA Sheet - Popular curated problem list
  • • TakeUForward - YouTube channel with detailed explanations

Interview Tips

  • Always start with a brute force solution, then optimize
  • Think aloud - interviewers want to see your thought process
  • Clarify constraints and edge cases before coding
  • Write clean, readable code with proper variable names
  • Test your code with examples before saying it's done

Company-Specific Focus

  • • Google/Amazon: Heavy on graphs, trees, DP, system design
  • • Meta: Arrays, strings, medium-level DP
  • • Flipkart/Swiggy/Zomato: DSA + system design for senior roles
  • • TCS/Infosys: Basic DSA, focus on aptitude and speed