Solve the no connection puzzle: Difference between revisions

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6 5
18 tries</pre>
 
=={{header|Red}}==
<lang Red>Red ["Solve the no connection puzzle"]
 
points: [a b c d e f g h]
; 'links' series will be scanned by pairs: [a c], [a d] etc.
links: [a c a d a e b d b e b f c d c g d e d g d h e f e g e h f h]
allpegs: [1 2 3 4 5 6 7 8]
 
; check if two points are connected (then game is lost) i.e.
; both are have a value (not zero) and absolute difference is 1
connected: func [x y] [all [
x * y <> 0
1 = absolute (x - y)
]]
; a list of points is valid if no connexion is found
isvalid: function [pegs [block!]] [
; assign pegs values to points, or 0 for remaining points
set points append/dup copy pegs 0 8
foreach [x y] links [if connected get x get y [return false]]
true
]
; recursively build a list of up to 8 valid points
check: function [pegs [block!]] [
if isvalid pegs [
rest: difference allpegs pegs
either empty? rest [
print rejoin ["Here is a solution: " pegs]
halt ; comment this line to get all solutions
][
foreach peg rest [check append copy pegs peg]
]
]
]
; start with and empty list
check []
</lang>
 
{{out}}
<pre>Here is a solution: 3 4 7 1 8 2 5 6
(halted)
</pre>
 
=={{header|REXX}}==
Anonymous user