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25 Stack, Queue, LinkedList Problems To Revise Before Interviews

· 5 min read

I've curated 25 Stack, Queue, LinkedList problems that teach you all major patterns. These aren't random problems, they're specifically chosen to build your intuition for technical interviews.

🎯 The Essential Problems​

Stack Problems​

1. Valid Parentheses - LeetCode 20

  • Pattern: Basic stack for matching
  • Why: Foundation for all parsing problems
  • Companies: Amazon, Microsoft, Meta, Bloomberg, Apple

2. Min Stack - LeetCode 155

  • Pattern: Auxiliary stack for O(1) operations
  • Why: Tests understanding of trade-offs (space vs time)
  • Companies: Amazon, Bloomberg, Microsoft

3. Implement Queue using Stacks - LeetCode 232

  • Pattern: Two stacks technique
  • Why: Tests understanding of both data structures
  • Companies: Microsoft, Bloomberg, Amazon

4. Daily Temperatures - LeetCode 739

  • Pattern: Monotonic stack
  • Why: Most important stack pattern for interviews
  • Companies: Amazon, Google, Meta, Bloomberg

5. Largest Rectangle in Histogram - LeetCode 84

  • Pattern: Monotonic stack for area calculation
  • Why: Hard problem that becomes medium with stack
  • Companies: Amazon, Google, Meta, Microsoft

6. Basic Calculator II - LeetCode 227

  • Pattern: Stack for expression evaluation
  • Why: Shows real-world stack application
  • Companies: Meta, Amazon, Google

Queue Problems​

7. Implement Stack using Queues - LeetCode 225

  • Pattern: Queue rotation technique
  • Why: Tests queue manipulation understanding
  • Companies: Bloomberg, Microsoft

8. Design Circular Queue - LeetCode 622

  • Pattern: Array-based queue with wraparound
  • Why: Tests boundary handling and modular arithmetic
  • Companies: Amazon, Microsoft, Meta

9. Moving Average from Data Stream - LeetCode 346

  • Pattern: Queue for sliding window
  • Why: Shows queue in streaming context
  • Companies: Amazon, Google, Meta

Linked List Problems​

10. Reverse Linked List - LeetCode 206

  • Pattern: Iterative and recursive reversal
  • Why: Most important linked list operation
  • Companies: Everyone

11. Merge Two Sorted Lists - LeetCode 21

  • Pattern: Two pointer merge
  • Why: Foundation for merge sort, merge operations
  • Companies: Amazon, Microsoft, Meta, Apple

12. Remove Nth Node From End of List - LeetCode 19

  • Pattern: Two pointer (fast/slow)
  • Why: Classic two-pointer technique
  • Companies: Amazon, Meta, Bloomberg

13. Linked List Cycle - LeetCode 141

  • Pattern: Floyd's cycle detection (fast/slow pointers)
  • Why: Fundamental algorithm, shows up in many forms
  • Companies: Amazon, Microsoft, Meta, Apple

14. Linked List Cycle II - LeetCode 142

  • Pattern: Finding cycle start with math
  • Why: Advanced pointer manipulation
  • Companies: Amazon, Microsoft, Meta

15. Intersection of Two Linked Lists - LeetCode 160

  • Pattern: Length difference or two-pointer technique
  • Why: Tests pointer manipulation cleverness
  • Companies: Amazon, Microsoft, Bloomberg

16. Palindrome Linked List - LeetCode 234

  • Pattern: Find middle + reverse + compare
  • Why: Combines multiple linked list patterns
  • Companies: Amazon, Meta, Microsoft

17. Remove Duplicates from Sorted List - LeetCode 83

  • Pattern: Single pass deletion
  • Why: Basic pointer manipulation
  • Companies: Amazon, Microsoft

Advanced Problems​

18. LRU Cache - LeetCode 146

  • Pattern: Hash map + doubly linked list
  • Why: System design favorite, tests multiple skills
  • Companies: Amazon, Meta, Microsoft, Google, Apple

19. Add Two Numbers - LeetCode 2

  • Pattern: Linked list arithmetic with carry
  • Why: Tests edge case handling
  • Companies: Amazon, Microsoft, Meta, Bloomberg

20. Reverse Nodes in k-Group - LeetCode 25

  • Pattern: Segmented reversal
  • Why: Hard problem, builds on reverse linked list
  • Companies: Meta, Amazon, Microsoft

21. Copy List with Random Pointer - LeetCode 138

  • Pattern: HashMap or interweaving technique
  • Why: Tests deep copy understanding
  • Companies: Amazon, Microsoft, Meta

22. Sort List - LeetCode 148

  • Pattern: Merge sort on linked list
  • Why: Combines sorting with linked list operations
  • Companies: Amazon, Meta, Microsoft

23. Reorder List - LeetCode 143

  • Pattern: Find middle + reverse + merge
  • Why: Combines three core operations
  • Companies: Amazon, Meta, Microsoft

24. Flatten a Multilevel Doubly Linked List - LeetCode 430

  • Pattern: Stack or recursion for nested structures
  • Why: Tests handling of complex pointer structures
  • Companies: Amazon, Microsoft

25. Design Browser History - LeetCode 1472

  • Pattern: Doubly linked list or array
  • Why: Real-world application of linked list
  • Companies: Amazon, Google

📚 Study Strategy​

Week 1-2: Master basic operations (problems 1-9, 10-12) Week 3-4: Two-pointer techniques and cycle detection (problems 13-17) Week 5-6: Advanced patterns and combinations (problems 18-25)

Practice these problems multiple times until you can code them without looking at solutions. Understanding the patterns is more important than memorizing solutions.