1-2 start/2005-12-25/1

really good brute force solver, you've made!

Are you sure

return solve(a, b, c+1, 0) if d==3 return solve(a, b+1, 0, d) if c==3 return solve(a+1, 0, c, d) if b==3

shouldn't be

return solve(a, b, c+1, 0) if d==3 return solve(a, b+1, 0, 0) if c==3 return solve(a+1, 0, 0, 0) if b==3

?

(I rewrote it in Ruby)

regards Christer