Applications of priority queues

[xecure]

I had an assignment due a couple of days ago asking how priority queues can be used to improve efficiency and benefit mapping software (ie. google maps, map quest)

 

I've search far and wide and only came up with these 2 points:

- they improve efficiency by assign a higher priority for locations searched more so they are accessed easier

- they allow programs to find the shortest path between two locations

 

My professor emailed me back saying I need atleast 3 more points as to why priority queues can be used to benefit mapping software. I'm totally stumped and can't find any other advantages to using them.

 

Can someone give me a few pointers?

Edited December 7, 2010 by xecure

[snowtea]

Can someone give me a few pointers?

 

Wikipedia is your friend

http://en.wikipedia.org/wiki/Priority_queue#Applications