OK - I¹ll take the bait although elegant algorithms definitely aren¹t my forte. As a result this is probably a very half-baked and inefficient solution to the problem but it seems to work and doesn¹t have to resort to recursion (which I can never get my head around) to generate the starting combinations. Instead I just repeatedly randomise the order of the items and sum them in that order until I get the required value.
Anyway, here goes (watch out for wrapped lines) Terry... on runIt put the seconds into tTimer put 100000000 into theTotal put "18897109,12828837,9461105,6371773,5965343,5946800,5582170,5564635,5268860, 4552402,4335391,4296250,4224851,4192887,3439809,3279833,3095313,2812896,278 3243,2710489,2543482,2356285,2226009,2149127,2142508,2134411" into tCityPops put empty into tKeys put 0 into tN repeat for each item tPop in tCityPops add 1 to tN put tPop into tPops[tN] put tN & comma after tKeys end repeat delete last char of tKeys put 0 into nIterations repeat forever add 1 to nIterations # randomise the order of the keys put randomiseItems(tKeys) into tX put 0 into tTotal repeat for each item tKey in tX add tPops[tKey] to tTotal if tTotal = theTotal then # we have a winner put itemOffset(tKey,tX) into nItem put item 1 to nItem of tX into tY sort items of tY ascending numeric answer ("Items = "&tY &cr& "nIterations = "&nIterations &cr& "Elapsed time = "&(the seconds - tTimer)&" secs") exit to top else if tTotal > theTotal then exit repeat end if end if end repeat end repeat end runIt function randomiseItems theItems put empty into tItems repeat forever put the number of items in theItems into nItems if nItems = 0 then exit repeat put random(nItems) into nItem put item nItem of theItems & comma after tItems delete item nItem of theItems end repeat delete last char of tItems return tItems end randomiseItems On 25/08/2014 9:52 am, "Michael Doub" <miked...@gmail.com> wrote: >I know that some of the folks on this list enjoy puzzles. A friend sent >me this one this afternoon and I thought it would be interesting to see >the different approaches folks come up with and how fast it can be >solved. enjoyŠ > >The 2010 Census puts populations of 26 largest US metro areas at >18897109, 12828837, 9461105, 6371773, 5965343,5946800, 5582170, 5564635, >5268860, 4552402, 4335391, 4296250, 4224851, 4192887, 3439809, 3279833, >3095313,2812896, 2783243, 2710489, 2543482, 2356285, 2226009, 2149127, >2142508, and 2134411. > >Can you find a subset of these areas where a total of exactly 100,000,000 >people live, assuming the census estimates are exactly right? >_______________________________________________ >use-livecode mailing list >firstname.lastname@example.org >Please visit this url to subscribe, unsubscribe and manage your >subscription preferences: >http://lists.runrev.com/mailman/listinfo/use-livecode _______________________________________________ use-livecode mailing list email@example.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode