Stacks & QueuesLesson 18Free preview
DSA Stacks
This lesson is part of DSA · All levels
Summary
A stack is a LIFO (Last In First Out) data structure: the last element that enters is the first to exit, like a plate stack. The main operations are push to add and pop to take elements from the top, as well as peek to see the top without removing. Stacks are used for undo, backtracking, and evaluation of expressions.
Key points
- LIFO principle: the last to go in, the first to go out
- Major operations: push, pop, peek, and is_empty
- Can be implemented with array or linked list
- Useful for undo, recursion, and evaluation of postfix expressions
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