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Problem: Implement a Stack using Queues

Explore how to implement a last in, first out (LIFO) stack using only two queues, supporting core stack functions like push, pop, top, and empty. Understand how to reorder queue elements during push operations to maintain stack behavior. Learn the time and space complexity of this implementation and practice coding the solution in Python.

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Statement

Implement a last in, first out (LIFO) stack using only two queues. The implemented stack should support all the functions of a normal stack (push, top, pop, and empty).

Implement the MyStack class:

  • void push(int x): Pushes element x to the top of the stack.

  • int pop(): Removes the element on the top of the stack and returns it.

  • int top(): Returns the element on the top of the stack.

  • boolean empty(): Returns true if the stack is empty, false otherwise.

Note: You must use only standard queue operations, which means only push to back, peek/pop from front, size, and is empty operations are valid. Depending on your language, the queue may not be supported natively. You may use a deque or list as long as you use only standard queue operations.

Constraints:

  • ...