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Coderust: Hacking the Coding Interview

Implement Stack Using Queues

Explore how to implement a stack data structure using two queues by defining push, pop, and isEmpty operations. Understand the two main algorithmic approaches that optimize either push or pop efficiency, with clear examples and analysis of their time and space complexities.

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Statement

Given a Queue class with common operations such as enqueue(), dequeue(), and size(), implement a Stack class with push(), pop(), and isEmpty() operations. The isEmpty() function should return true if the stack is empty and false otherwise.

Note: If the stack is empty, the pop() function should return −1-1.

A stack is a data structure in which objects are inserted and removed according to the LIFOLast In First Out principle. An item is added at the top of the stack and removed from the top as well. There are two important functionalities of the stack:

  • push(): Inserts an item at the top of the stack.
  • pop(): Removes an item from the top of the stack and returns it.

A queue is a data structure in which objects are inserted and removed according to the FIFOFirst In First Out principle, ...