I'm working on LightOJ problem 1002 and I can see that the problem requires a variant of Dijkstra's algorithm. When I refer to books, however, they require a different type of PriorirtyQueue than what is included in Java's Collections library.

My question is, for those of you who have had to implement Dijkstra's in a contest or even from an OJ while practicing, have you had to write your own Heap and PriorityQueue implementation usually, or is there a quicker way? I've been told before that TreeSet could be used in replacement for PriorityQueue. I've tried to look around a bit for shortest path tagged problems and how people have used Dijkstra's here on Codeforces, but implementations seem to vary so drastically, and it makes it quite confusing to know which style to follow and study. Could someone show me an example of how they implement Dijkstra's algorithm for contests in Java. It would be really helpful to learn from and reference from. Thanks.