can someone give me a simple explaination  of what a PriorityQueue actually does? 

Well, in C++, the std priority queue allows you to add things to the list of items with a certain level of importance, or priority. Items with the most priority appear at the beginning of the list, items with less priority appear after the more important ones. It's a pretty simple concept.

A queue is a first-in-first-out data structure.  That means that the first object put into it is the first object taken out of it.

A priority queue is a modification of a queue in which higher priority items are removed first.

yallz gotta get one of dem O(log n) heaps up in hurrrrrrrrrrrrrrrrrrr