Consider the stack-based search of the flight map in the HP Air problem of Chapter 6 . You can replace the stack that searchs uses with a queue. That is, you can replace every call to push with a call to enqueue, every call to pop with a call to dequeue, and every call to peek with a call to peek Front. Trace the resulting algorithm when you fly from P to Z in the flight map in Figure 6-6 . Indicate the contents of the queue after every operation on it.