This looks like a transliteration from another language - not J-like at all. Once clue is that it's several times as long as many of the other implementations.
On Mon, Sep 8, 2014 at 4:05 PM, Joe Bogner <joebog...@gmail.com> wrote: > I found an implementation of red-black trees on rosettacode: > http://rosettacode.org/wiki/Pattern_matching#J ... It might be relevant > or > may not be. > > On Mon, Sep 8, 2014 at 3:45 PM, Devon McCormick <devon...@gmail.com> > wrote: > > > A little research clarified what we see here: apparently it's part of the > > definition of a binary tree that the left node be smaller than its parent > > but the right one is greater. Right away, I see a problem for the > > predecessor-index representation of a tree that I'm advocating as it does > > not distinguish between right and left nodes as it is usually > implemented. > > > > > > On Mon, Sep 8, 2014 at 3:03 PM, Devon McCormick <devon...@gmail.com> > > wrote: > > > > > Do you have a reference to a good example of this? Looking at the > > > "before" and "after" pictures on the right here - > > > http://en.wikipedia.org/wiki/Self-balancing_binary_search_tree - the > > > rebalancing seems arbitrary as it preserves some relations but changes > > > others. > > > > > > > > > On Mon, Sep 8, 2014 at 2:30 PM, Dan Bron <j...@bron.us> wrote: > > > > > >> Raul wrote: > > >> > Note that J already supports trees. > > >> > > >> Devon wrote: > > >> > I have J code that uses trees which I run daily and > > >> > have been doing so for years. > > >> > > >> Pascal wrote: > > >> > I think trees are done at least ok, if not "right" already. > > >> > > >> Challenge: express, in J, the logic of rebalancing a heap (say, a > > >> Fibonacci > > >> heap, but I'm not particularly picky). > > >> > > >> For the sake of this exercise, you may ignore considerations of > > efficiency > > >> (though that's a bit of a self-contradiction, because heaps are > > frequently > > >> introduced specifically for the sake of efficiency). I am only > > interested > > >> in the directness, simplicity, elegance (lyricality) of the notation, > in > > >> its current form, for expressing ideas about trees. We can make it > > >> efficient "later" (Pepe's TCO utility is a start). > > >> > > >> -Dan > > >> > > >> > > >> > > >> ---------------------------------------------------------------------- > > >> For information about J forums see > http://www.jsoftware.com/forums.htm > > >> > > > > > > > > > > > > -- > > > Devon McCormick, CFA > > > > > > > > > > > > -- > > Devon McCormick, CFA > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Devon McCormick, CFA ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
