Im wondering if I can optimize my pathfinding code a bit, lets look at this map:
+ - wall, . - free, S - start, F - finish
.S.............
...............
..........+++..
..........+F+..
..........+++..
...............
The human will look at it and say its impossible, becouse finish is surrounded… But A-star MUST check all fields to ascertain, that there isnt possible road. Well, its not a problem with small maps. But when I have 256×265 map, it takes a lot of time to check all points. I think that i can stop searching while there are closed nodes arround the finish, i mean:
+ - wall, . - free, S - start, F - finish, X - closed node
.S.............
.........XXXXX.
.........X+++X.
.........X+F+X.
.........X+++X.
.........XXXXX.
And I want to finish in this situation (There is no entrance to “room” with finish). I thought to check h, and while none of open nodes is getting closer, then to finish… But im not sure if its ok, maybe there is any better way?
Thanx for any replies.
First of all this problem is better solved with breadth-first search, but I will assume you have a good reason to use a-star instead. However I still recommend you first check the connectivity between S and F with some kind of search(Breadth-first or depth-first search). This will solve our issue.