Must know coding programs for FAANG companies

If you are mid or senior developer preparing for coding rounds ,these are the most frequently asked questions. By going through these programs , you will be able to clear almost all FAANG interviews as well.

Top Leetcode programs for FAANG companies
Top Leetcode programs for FAANG companies

First we need to understand different patterns to solve these problems.
There is no need to solve 500-1000 problems. All we need to do is identify which problem falls under which pattern. This will come by practice.

If you are someone who has interview in a month’s time . I think these programs will help you clear your coding rounds.

Lets understand different patterns to solve these problems:

1. Sliding Window

Best for: Problems asking about continuous sections of arrays or strings, especially when you need to track something within a fixed or variable-size range.

Core concept: Keep a window of elements and adjust its boundaries as you move through the data structure.

Try these:

2. Two Pointers

Best for: Working with sorted data structures or when you need to compare elements from different positions efficiently.

Core concept: Position two references at strategic points and move them based on your logic to avoid nested loops.

Try these:

3. Fast & Slow Pointers

Best for: Cycle detection and finding specific positions in sequences, particularly in linked structures.

Core concept: Move two references at different speeds — eventually they’ll meet if there’s a loop, or you’ll find what you’re looking for.

Try these:

4. Interval Merging

Best for: Scheduling conflicts, time range problems, or any situation with overlapping ranges.

Core concept: Sort by start times, then combine ranges that touch or overlap.

Try these:

5. Cyclic Sort

Best for: Arrays with numbers in a specific range where each number has a “correct” position.

Core concept: Keep swapping elements until each number sits at its intended index.

Try these:

6. Linked List Reversal

Best for: Flipping connections in linked lists without allocating new memory.

Core concept: Track previous, current, and next nodes while rewiring connections one step at a time.

Try these:

7. Level-Order Traversal (BFS)

Best for: Processing tree or graph nodes one layer at a time, finding shortest paths in unweighted structures.

Core concept: Use a queue to handle all nodes at each depth before moving deeper.

Try these:

8. Depth-First Exploration (DFS)

Best for: Exploring every possible path in trees or graphs, checking all branches thoroughly.

Core concept: Go as far down one path as possible before backing up and trying another route.

Different approaches:

  • Visit root first (PreOrder)
  • Visit root between children (InOrder)
  • Visit root after children (PostOrder)

Try these:

9. Adaptive Binary Search

Best for: Sorted data with twists like rotations, 2D sorted matrices, or finding boundaries.

Core concept: Modify traditional binary search logic to handle special array configurations while keeping logarithmic time.

Try these:

10. Heap for Top Elements

Best for: Finding K largest, smallest, or most frequent items without fully sorting.

Core concept: Maintain a heap of size K — only keep the elements you care about.

Try these:

11. Multi-List Merging

Best for: Combining multiple sorted sequences efficiently.

Core concept: Track the smallest current element from each list using a heap, then advance in that list.

Try these:

12. Dependency Ordering

Best for: Task scheduling where some items must come before others.

Core concept: Build a dependency graph, then process items that have no prerequisites first, gradually working through the chain.

Try these:

13. Cumulative Sum Technique

Best for: Answering many range queries quickly, or finding subarrays with specific sum properties.

Core concept: Build an array where each position stores the total of all previous elements, making range calculations instant.

Try these:

14. Order-Maintaining Stack

Best for: Finding next larger/smaller values, maintaining increasing/decreasing sequences.

Core concept: Keep a stack that maintains specific ordering, removing elements that break that order.

Try these:

15. Grid Navigation

Best for: 2D array problems involving connected regions, pathfinding, or area calculations.

Core concept: Move through adjacent cells systematically, marking visited locations to avoid redundant work.

Try these:

16. Dynamic Programming

Best for: Optimization questions where you need the best solution, problems with overlapping smaller versions of the same question.

Common scenarios:

  • Fibonacci-style sequences
  • Resource allocation with constraints
  • Finding longest common patterns
  • Subset selection problems

Core concept: Break big problems into smaller ones, remember solutions to avoid recalculation.

Try these:

🟢 EASY (16 problems)

1. Two Sum — Arrays

2. Best Time to Buy and Sell Stock — Arrays, Dynamic Programming –Solution

3. Valid Parentheses — Strings, Stacks — Solution

4. Longest Common Prefix — Arrays, Strings — Solution

5. Merge Sorted Array — Arrays, Two Pointers — Solution

6. Roman to Integer — Strings — Solution

7. Palindrome Number — Bit Manipulation — Solution

8. Move Zeroes — Arrays, Two Pointers — Solution

9. Valid Anagram — Strings — Solution

10. Reverse Linked List — Linked Lists, Recursion — Solution

11. Merge Two Sorted Lists — Linked Lists — Solution

12. Valid Palindrome — Strings, Two Pointers — Solution

13. Remove Duplicates from Sorted Array — Arrays, Two Pointers — Solution

14. Contains Duplicate — Arrays — Solution

15. Climbing Stairs — Dynamic Programming — Solution

16. Majority Element — Arrays — Solution

🟡 MEDIUM (48 problems)

1. Merge Intervals — Arrays, Sorting — Solution

2. Longest Substring Without Repeating Characters — Strings, Two Pointers, Sliding Windows — Solution

3. Number of Islands — Graphs, Arrays — Solution

4. Group Anagrams — Arrays, Strings — Solution

5. Longest Palindromic Substring — Strings, Dynamic Programming — Solution

6. Top K Frequent Elements — Arrays, Greedy Algorithms — Solution

7. 3Sum — Arrays, Two Pointers — Solution

8. Subarray Sum Equals K — Arrays, Sliding Windows — Solution

9. Search in Rotated Sorted Array — Arrays, Binary Search — Solution

10. Maximum Subarray — Arrays, Dynamic Programming — Solution

11. Rotate Image — Arrays — Solution

12. Spiral Matrix — Arrays — Solution

13. Add Two Numbers — Linked Lists — Solution

14. Kth Largest Element in an Array — Arrays, Two Pointers — Solution

15. Generate Parentheses — Recursion, Strings — Solution

16. Rotting Oranges — Arrays, Graphs — Solution

17. Find First and Last Position of Element in Sorted Array — Arrays, Binary Search — Solution

18. House Robber — Arrays, Dynamic Programming — Solution

19. Container With Most Water — Arrays, Two Pointers, Greedy Algorithms — Solution

20. Meeting Rooms II — Arrays, Greedy Algorithms, Dynamic Programming — Solution

21. Coin Change — Dynamic Programming — Solution

22. Product of Array Except Self — Arrays — Solution

23. Longest Consecutive Sequence — Arrays — Solution

24. Koko Eating Bananas — Arrays, Binary Search — Solution

25. Jump Game — Arrays, Greedy Algorithms — Solution

26. Integer to Roman — Strings — Solution

27. Course Schedule — Graphs, Recursion — Solution

28. Next Permutation — Arrays, Two Pointers — Solution

29. Course Schedule II — Graphs, Dynamic Programming — Solution

30. Find Peak Element — Arrays, Binary Search — Solution

31. Best Time to Buy and Sell Stock II — Arrays, Greedy Algorithms — Solution

32. Subsets — Arrays, Recursion, Bit Manipulation — Solution

33. Rotate Array — Arrays — Solution

34. Min Stack — Stacks — Solution

35. Word Break — Strings, Dynamic Programming — Solution

36. Word Search — Arrays, Recursion — Solution

37. Longest Increasing Subsequence — Arrays, Binary Search, Dynamic Programming — Solution

38. Reorganize String — Strings, Greedy Algorithms, Arrays — Solution

39. String Compression — Arrays, Strings, Two Pointers — Solution

40. Sort Colors — Arrays, Two Pointers — Solution

41. Jump Game II — Arrays, Greedy Algorithms — Solution

42. Decode String — Strings, Stacks, Recursion — Solution

43. Copy List with Random Pointer — Linked Lists, Recursion, Arrays — Solution

44. Valid Sudoku — Arrays — Solution

45. Letter Combinations of a Phone Number — Strings, Recursion — Solution

46. Daily Temperatures — Arrays, Stacks — Solution

47. Pow(x, n) — Recursion, Bit Manipulation — Solution

48. Simplify Path — Strings, Stacks — Solution

🔴 HARD (10 problems)

1. Trapping Rain Water [V.Imp] — Arrays, Two Pointers, Dynamic Programming, Stacks — Solution

2. Median of Two Sorted Arrays — Arrays, Binary Search — Solution

3. Merge k Sorted Lists — Linked Lists, Arrays, Greedy Algorithms — Solution

4. Minimum Window Substring — Strings, Sliding Windows — Solution

5. Sliding Window Maximum — Arrays, Sliding Windows — Solution

6. Word Ladder [V.Imp]— Graphs, Strings — Solution

7. Binary Tree Maximum Path Sum [V.Imp]— Trees, Recursion — Solution

8. Candy — Arrays, Greedy Algorithms — Solution

9. LFU Cache — Linked Lists, Arrays, Dynamic Programming — Solution

10. Basic Calculator — Stacks, Strings — Solution

I have searched about solutions for all these problems. There are some of the useful youtube channels you can follow for detailed explanations.

  1. Tushar Roy — https://www.youtube.com/@tusharroy2525
  2. Parth Vyas — https://www.youtube.com/@DestinationFAANG
  3. TakeUForward — https://www.youtube.com/@takeUforward
  4. NeetCode — https://www.youtube.com/@NeetCode
  5. Ashish Pratap Singh — https://www.youtube.com/@ashishps_1
  6. Greg Hogg — https://www.youtube.com/@GregHogg
  7. FreeCodeCamp — https://www.youtube.com/@freecodecamp

I know this seems to be Overwhelming. But trust me with practise you will be able to clear almost all the coding rounds with these questions. Just focus on atleast easy and medium problems. The hard problems just choose the most important questions. Let me know if you follow any other youtube channels for coding round preparation. Lets all help each other to progress and crack interviews.

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