Implement Stack using Two Queues

Question

A similar question was asked earlier there, but the question here is the reverse of it, using two queues as a stack. The question...

Given two queues with their sta

Answer 1

Here is some simple pseudo code, push is O(n), pop / peek is O(1):

Qpush = Qinstance()
Qpop = Qinstance()

def stack.push(item):
    Qpush.add(item)
    while Qpop.peek() != null: //transfer Qpop into Qpush
        Qpush.add(Qpop.remove()) 
    swap = Qpush
    Qpush = Qpop
    Qpop = swap

def stack.pop():
    return Qpop.remove()

def stack.peek():
    return Qpop.peek()