A Stack is a fundamental data structure that follows the Last In, First Out (LIFO) principle. The last element pushed into the stack is the first one removed. Common operations include push, pop, peek, and checking whether the stack is empty. Stacks are widely used in programming for managing function calls, parsing expressions, undo/redo systems, and solving many algorithmic problems.
In coding interviews, stack-based problems frequently appear because they test your understanding of data structure behavior and your ability to model constraints efficiently. Many classic interview questions—such as valid parentheses, next greater element, and evaluating postfix expressions—rely heavily on stack logic. You’ll often combine stacks with structures like Array for implementation or with traversal strategies like Depth-First Search when exploring trees and graphs.
As you advance, you’ll encounter powerful patterns like the Monotonic Stack, which helps solve problems involving next greater/smaller elements, histogram areas, and range queries efficiently. Understanding how stacks compare to related structures like Queue also helps clarify when LIFO behavior is the right choice.
On this page, you’ll find 163 carefully curated Stack practice problems ranging from beginner-friendly exercises to advanced interview challenges used by top tech companies.
Many stack implementations use arrays, and several interview problems combine array traversal with stack operations.
Learning the difference between FIFO and LIFO structures helps clarify when a stack is the correct approach.
Recursion relies on the call stack internally, making it easier to understand stack behavior and backtracking logic.
An advanced stack pattern used to efficiently solve next greater element, histogram, and range-based problems.
DFS uses a stack implicitly or explicitly, making stack knowledge important for graph and tree traversal.
Start Easy, progress to Hard.
Frequently appear alongside Stack.
Common questions about Stack.
A stack is a linear data structure that follows the Last In, First Out (LIFO) rule. Elements are added using push and removed using pop, meaning the most recently added item is processed first.
Use a stack when the most recently added element should be processed first, such as in undo systems or expression parsing. A queue is better when tasks must be processed in the order they arrive.
Stacks can be implemented using either arrays or linked lists. Arrays are simpler and faster in most cases, while linked lists allow dynamic growth without resizing.
Typical patterns include balanced parentheses, next greater or smaller element, monotonic stacks, expression evaluation, and using stacks for DFS or backtracking problems.
Practicing 50–100 well‑selected stack problems is usually enough to master common patterns. Platforms like TalentD provide curated sets so you can focus on frequently asked interview questions.