REBOL [ Author: "Christian Blanvillain" Name: 'CompteEstBon Title: "Le Compte est Bon." File: %ceb.r Date: 1-May-2008 Version: 1.0 Purpose: "Algorithm to solve french countdown game." Library: [ level: 'intermediate platform: 'all type: [game fun] domain: [math game] tested-under: none support: none license: none see-also: none ] ] target: 952 list: [ 3 6 25 50 75 100 ] kronos: make time! now/time op: [+ - * /] ad: func[x y][x + y] sb: func[x y][x - y] ml: func[x y][if error? try [return x * y][0]] dv: func[x y][either (x // y) = 0 [x / y][0]] calculs: func[x y][make block! [(ad x y) (sb x y) (ml x y) (dv x y)]] nwlist: func[list j i res][sort append head remove at head remove at copy list j i res] hash: make hash! 1 ceb: function[list size][ol][ if (not select hash mold list) [ hash: append append hash mold list true for i 1 (size - 1) 1 [ for j (i + 1) size 1 [ ol: reduce calculs list/:j list/:i for k 1 4 1 [ if any [(ol/:k = target) all [(ol/:k <> 0) (size > 1) (s: ceb (nwlist list j i ol/:k) (size - 1))]] [ return rejoin [list/:j op/:k list/:i "=" ol/:k newline s] ] ] ] ] ] return false ] print rejoin ["^(1B)[J" ceb list length? list newline (now/time - kronos) " sec."]