wireless_keyboard_codegolf.jl

# implement WirelessKeyboard as K
immutable K
    f::Int
    s::Int
end
# implement InterferesWith as <
>(k::K,K::K)=k.f==K.f
#prepare randomized array
k = [K(f,(j-1)*3+f) for j=1:12,f=1:3]
k9 = [K(f,(j-1)*3+f) for j=1:3,f=1:3] # smaller testing array
randomize!(a) = for j = 1:length(a); i = rand(j:length(a)); a[j],a[i] = a[i],a[j]; end
randomize!(k);randomize!(k9)
# implement algorithm (all golf code in next line)
s(k)=while any([k[j]>k[j-1]||j>6&&k[j]>k[j-6] for j=2:36]);i,j=rand(1:36,2);k[[i,j]]=k[[j,i]];end
# implement same algorithm for smaller array for testing
s9(k)=while any([k[j]>k[j-1]||j>3&&k[j]>k[j-3] for j=2:9]);i,j=rand(1:9,2);k[[i,j]]=k[[j,i]];end
# call smaller array test algorithm
s9(k9)
println(k9) # display result
# call full algorithm
s(k)
println(k) # display result

Since the algorithm is so slow I left it running overnight, and came back to a correct solution.

julia> kr = reshape(k,(6,6))
6x6 Array{K,2}:
K(2,5) K(3,12) K(1,25) K(3,30) K(1,19) K(3,33)
K(3,9) K(1,10) K(2,20) K(1,22) K(3,18) K(1,28)
K(2,32) K(3,21) K(1,16) K(2,11) K(1,13) K(2,35)
K(3,3) K(1,7) K(2,8) K(1,31) K(2,29) K(1,34)
K(1,1) K(2,23) K(3,6) K(2,26) K(3,24) K(2,17)
K(2,14) K(3,27) K(2,2) K(3,36) K(1,4) K(3,15)