Stack: Master the Fundamentals

A stack is a LIFO (last-in, first-out) data structure. It appears in parsing, expression evaluation, backtracking, and many interview problems. This guide covers stack basics and the main patterns; each concept links to a detailed page.

What Is a Stack?

Operations: push (add on top), pop (remove from top), peek/top (read top). Optional: isEmpty, size. All in O(1) when implemented with an array or linked list. Use a stack when you need to process elements in reverse order of arrival or to match pairs (e.g. brackets).

Core Concepts

Learning Path

Start with: Stack Basics, Valid Parentheses, Min Stack.

Then: Monotonic Stack, Next Greater Element, Daily Temperatures, Largest Rectangle in Histogram.

Advanced: Decode String, Basic Calculator, Remove K Digits.

Summary

Stack problems often involve matching pairs (parentheses), monotonic stacks (next greater/smaller), or parsing (decode string, calculator). Use the concept links above for detailed guides and examples.

Stack Algorithms

Stack - Complete Guide

Stack: Master the Fundamentals

What Is a Stack?

Core Concepts

1. Stack Basics

2. Valid Parentheses

3. Min Stack

4. Monotonic Stack

5. Next Greater Element

6. Daily Temperatures

7. Largest Rectangle in Histogram

8. Decode String

9. Queue using Stacks

10. Remove Adjacent Duplicates

11. Score of Parentheses

12. Asteroid Collision

13. Simplify Path

14. Basic Calculator

15. Remove K Digits

16. Design Stack

Learning Path

Summary