<div dir="ltr">I understood you to be asking for something like this:<div><br></div><div><div> (check-equal? (uf-same-set? (uf-new 1) (uf-new 2)) #f)</div><div> (check-equal? (uf-same-set? (uf-new 1) (uf-new 1)) #f)</div> <div> (check-equal? (let ([a (uf-new 1)]</div><div> [b (uf-new 1)])</div><div> (uf-union! a b) </div><div> (uf-same-set? a b))</div><div> #t)</div></div> <div><br></div><div style>No?</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Jan 29, 2013 at 6:51 PM, Sam Tobin-Hochstadt <span dir="ltr"><<a href="mailto:samth@ccs.neu.edu" target="_blank">samth@ccs.neu.edu</a>></span> wrote:<br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">But wouldn't that equate two un-unioned invocations of (uf-new 1)?<br> <br> On Tue, Jan 29, 2013 at 7:47 PM, Robby Findler<br> <div class="HOEnZb"><div class="h5"><<a href="mailto:robby@eecs.northwestern.edu">robby@eecs.northwestern.edu</a>> wrote:<br> > But I should probably provide that, since it can be done more reliably<br> > inside the library.<br> ><br> > Robby<br> ><br> ><br> > On Tue, Jan 29, 2013 at 6:46 PM, Robby Findler <<a href="mailto:robby@eecs.northwestern.edu">robby@eecs.northwestern.edu</a>><br> > wrote:<br> >><br> >><br> >><br> >><br> >> On Tue, Jan 29, 2013 at 4:20 PM, Sam Tobin-Hochstadt <<a href="mailto:samth@ccs.neu.edu">samth@ccs.neu.edu</a>><br> >> wrote:<br> >>><br> >>> This is probably a silly question, but don't you also need some way to<br> >>> check if two sets have been unioned? Does your application not need<br> >>> that?<br> >>><br> >><br> >> You check to see if their canonical element is the same.<br> >><br> >> Robby<br> >><br> >>><br> >>> Sam<br> >>><br> >>> On Tue, Jan 29, 2013 at 4:51 PM, Robby Findler<br> >>> <<a href="mailto:robby@eecs.northwestern.edu">robby@eecs.northwestern.edu</a>> wrote:<br> >>> > I've just pushed an implementation of the union-find algorithm to the<br> >>> > data/<br> >>> > collection. I didn't do it quite the way wikipedia recommends, but<br> >>> > instead<br> >>> > made the sets be little containers whose canonical element can be<br> >>> > mutated.<br> >>> ><br> >>> > This suits my purposes well, but I wanted to ask if someone on the list<br> >>> > knows why the wikipedia way is better.<br> >>> ><br> >>> > Also, I wasn't sure about the names, so I put "uf-" on the front of<br> >>> > everything to discourage people from using this when they really want<br> >>> > racket/set. Maybe there is a better way, tho?<br> >>> ><br> >>> > Robby<br> >>> ><br> >>> ><br> >>> > _________________________<br> >>> > Racket Developers list:<br> >>> > <a href="http://lists.racket-lang.org/dev" target="_blank">http://lists.racket-lang.org/dev</a><br> >>> ><br> >><br> >><br> ><br> </div></div></blockquote></div><br></div>