Reverse Polish Notation (RPN), also known as postfix notation, is a useful format for calculators and expression evaluation because it...

Maintaining a stack that can return its minimum value in constant time is a neat warm‑up that mirrors real‑world needs like tracking the...

Building a queue out of stacks is a classic exercise in adapting one data structure to mimic another. It’s not only a great warm‑up for...

Checking whether a string of parentheses is valid is one of the most common warm‑ups in interviews. It’s directly applicable to parsing...