Shortest path in JavaScript

Question

I have been searching for weeks for a way to compute shortest paths in JavaScript. I have been playing with the book Data Structures and Algorithms by Groner (aptly nam

Answer 1

Reading your question, I can read it one of two ways... Either you're trying to reduce the amount of things it checks, or you're trying to allow yourself to pass in variables to change end points. I'm going to assume the former and let someone else handle the latter case.

Giving a cursory glance over the problem, it looks like you've come across what is known in Comp Sci as "The traveling salesman problem." It's a classical problem in computer programming that's considered a logical impossibility, and is a good example of "perfect being the enemy of the good."

The classical travelling salesman problem is this, "Program a way for a salesman to reach all of his destination cities on a map in the shortest time. Do so without having to check every single possible path." The thing is, logical way to do this has (yet) to ever be discovered (it's yet to be proved if it's impossible or possible). That said, if it doesn't have to be THE shortest, but just a shorter path, there's a number of shortcuts that can be taken. One example is just calculating a line from start to finish, and then push in the deviations to match up with closest vertices. Another is to break the paths into triangles that connect each vertices only to the next closest two vertices and then connect clumps the same way until all vertices are connected and then only calculate your starting potential paths from those subsets.

Neither of those two answers are guaranteed to give you the best answer, but they will provide a good answer with a lot less computational time required so you don't have to calculate every path coming from A and B and C etc. etc.