Stack & Queue Topics

Master essential stack and queue problems and patterns frequently asked in interviews.

•   01 Valid Parentheses Balanced parentheses check using stack
•   02 Min Stack Design stack with O(1) min retrieval
•   03 Next Greater Element Monotonic stack pattern for array problems
•   04 Implement Queue using Stacks Classic stack-to-queue conversion
•   05 Sliding Window Maximum Deque-based optimization for window problems

WONDERING, HOW DOES IT COVER PATTERNS?
These problems cover the most important stack and queue patterns for interviews:

Valid Parentheses → Balanced brackets, stack push-pop matching.
Min Stack → Design problems, auxiliary stack technique.
Next Greater Element → Monotonic stack, array traversal.
Implement Queue using Stacks → Stack-Queue conversion, data structure simulation.
Sliding Window Maximum → Deque pattern, window-based optimization.

Together, they ensure you understand stack-based matching, design with auxiliary structures, monotonic stack tricks, stack-to-queue conversions, and sliding window optimization using queues.