What is a monotonic stack and when would you use one?

Heisenbug logo
TheHeisenBug

Search

Search across questions, learning content, and hands-on projects

Ace Your Next Tech Interview

5,986+ interview questions across 87 technologies — with expert answers, advanced search, AI-powered assistance, personal highlights, structured learning paths, and hands-on practice projects.

5,986+Questions & Answers
87Technologies
AdvancedSearch
Built-inAsk AI
PersonalHighlights
StructuredLearning Paths
Hands-onPractice Projects

Lifetime Access

One-time payment. No subscriptions. Unlock everything, forever.

$19.90USD

or R$49.90 BRL

FeatureFreePremium
Question titlesAllAll
Answers per topicTop 5All
Learning chaptersFirst 5All
Practice projectsFirst 3All
Highlights✓✓
Ask AI—✓
Read tracking✓✓
Search✓✓

Stacks & Queues Interview Questions

  1. [JUNIOR] What is a stack and how does the LIFO (Last In, First Out) principle work?
  2. [JUNIOR] What is a queue and how does the FIFO (First In, First Out) principle work?
  3. [JUNIOR] What are the primary operations of a stack and what are their time complexities?
  4. [JUNIOR] What are the primary operations of a queue and what are their time complexities?
  5. [JUNIOR] What is the difference between a stack and a queue?
  6. [MID] How do you implement a queue using two stacks?
  7. [MID] How do you design a min stack that supports push, pop, and getMin in O(1) time?
  8. [MID] How do you evaluate a postfix (Reverse Polish Notation) expression using a stack?
  9. [SENIOR] How do you solve the largest rectangle in a histogram problem using a stack?
  10. [JUNIOR] How can a stack be implemented using an array?
  11. [JUNIOR] How can a stack be implemented using a linked list?
  12. [JUNIOR] How do you check for balanced parentheses using a stack?
  13. [MID] How do you implement a stack using two queues?
  14. [MID] How do you convert an infix expression to postfix notation using a stack?
  15. [MID] How do you solve the next greater element problem using a stack?
  16. [MID] What is a monotonic stack and when would you use one?
  17. [SENIOR] How do you solve the trapping rain water problem using a stack-based approach?
  18. [SENIOR] How do you implement a basic calculator that evaluates expressions with parentheses and operators?
  19. [SENIOR] How do you solve the sliding window maximum problem using a deque?
  20. [JUNIOR] What is stack overflow and stack underflow?
  21. [JUNIOR] How do you reverse a string using a stack?
  22. [JUNIOR] What are some real-world applications of stacks?
  23. [JUNIOR] What are some real-world applications of queues?
  24. [MID] How are stacks used in function call management and recursion in programming languages?
  25. [MID] What is the stock span problem and how do you solve it using a stack?
  26. [MID] How do you sort a stack using only another temporary stack?
  27. [MID] How do you solve the daily temperatures problem using a monotonic stack?
  28. [SENIOR] How do you find the longest valid parentheses substring?
  29. [SENIOR] How do you remove K digits from a number string to make it the smallest possible using a stack?
  30. [SENIOR] How do you implement a maximum frequency stack that always pops the most frequent element?
  31. [JUNIOR] What is a priority queue and how does it differ from a regular queue?
  32. [JUNIOR] What is a deque (double-ended queue) and what operations does it support?
  33. [MID] How do you reverse a stack using only recursion without any extra data structure?
  34. [MID] How do you design and implement a circular queue?
  35. [MID] How do you solve the asteroid collision problem using a stack?
  36. [MID] How does the decode string problem use a stack to handle nested encoded patterns?
  37. [SENIOR] How do you solve the maximal rectangle of all 1s in a binary matrix using a stack?
  38. [SENIOR] How do you implement K stacks efficiently in a single array?
  39. [JUNIOR] What is a circular queue and why is it useful?
  40. [JUNIOR] Why is a stack considered a recursive data structure?
  41. [MID] How do you delete the middle element of a stack without using any additional data structure?
  42. [MID] What are infix, prefix, and postfix notations and how do stacks help convert between them?
  43. [MID] How do you remove all adjacent duplicates in a string using a stack?
  44. [SENIOR] How does the task scheduler problem use queue-based approaches to schedule tasks with cooldown periods?
  45. [SENIOR] How do you find the maximum of minimums for every window size using a stack?
  46. [EXPERT] How would you design a stack that supports push, pop, and getRandom all in O(1) time?
  47. [MID] When should you use a stack or queue instead of an array or linked list?
  48. [MID] How do you implement a stack using a single queue?
  49. [SENIOR] How do you solve the online stock span problem using a stack?
  50. [SENIOR] How do you solve the sum of subarray minimums problem using a monotonic stack?
  51. [EXPERT] How would you implement a stack with findMiddle() and deleteMiddle() operations in O(1) time?
  52. [EXPERT] How do you solve the constrained subsequence sum problem using a deque-based approach?
  53. [EXPERT] How do you solve the number of visible people in a queue problem using a stack?
  54. [EXPERT] How do you solve the stamping the sequence problem?
  55. [EXPERT] How would you design a lock-free concurrent stack or queue for multi-threaded environments?