Given a stack S, need to sort the stack using only Push, Pop, Top, IsEmpty, IsFull.
Looking for most sim
What temporary data structures can you use? With push and pop, and no temporary storage for n elements, accessing data near the bottom of the stack would be impossible without storing the rest -somewhere-.
If top (equiv to {x=pop();push(x);return x}) was replaced with shift, it would be perfectly doable - the stack would change into fifo (shift+push; pop would fall into disuse) and it would allow for an easy bubblesort on currently available elements.