(Sorry for the slow response .. I'm not doing AoC this year, among other things...)
If I were tackling AoC 6 this year, I think I would use https://rosettacode.org/wiki/K-means%2B%2B_clustering FYI, -- Raul On Sat, Dec 8, 2018 at 10:34 AM Brian Schott <[email protected]> wrote: > > I had quite a time doing day6 because after I computed all of the distances > for all the areas for each given vertex, I could not eliminate the infinite > vertices mathematically. For the 6-vertex the removal of infinite vertices > was simply a matter of finding the convex hull using transitive closure, > and then removing those vertices. But in the real data set, that was not > enough. From reading a comment on reddit.com (link below) I gathered that > one way to have found the set of all infinite areas would have been to give > the total area a large border so that the infinite areas seemed infinite > because of their disproportionately large area. > > https://www.reddit.com/r/adventofcode/comments/a3kr4r/2018_day_6_solutions/ > > But I did not try that because I discovered how to use viewmat to see the > 50+ areas and to use j's Amend on the array of minimum distances to > superimpose selective vertices as dots on the viewmat. Then I could see > (most of the areas -- not all of them because the color differentials were > not very contrasty for my color-defective eyes) the areas and visually > chase down the largest area. > > The viewmat approach mesmerized me a little, to be honest, but I am > wondering if another more mathematical approach could be used? I would be > happy to share my existing code, if that would be a better place to start. > But perhaps my description of my and your approach would be adequate. > > > Thanks, > > -- > (B=) <-----my sig > Brian Schott > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
