public int Pop()
{
MyStack last = GetLastStack();
if (last == null)
{
throw new NullReferenceException();
}
int item = last.Pop();
if (last.size == 0)
{
stacks.Remove(stacks[stacks.Count - 1]);
}
return(item);
}
public int LeftShift(int index, bool removeTop)
{
MyStack stack = stacks[index];
int removed_item;
removed_item = (removeTop) ? stack.Pop() : stack.RemoveBottom();
if (stack.IsEmpty())
{
stacks.Remove(stacks[index]);
}
else if (stacks.Count > index + 1)
{
int item = LeftShift(index + 1, false);
stack.Push(item);
}
return(removed_item);
}