The numeric keyboards of a telephone (left) and a pocket calculator (right) differ in the arrangement of the keys.

123   789
456   456
789   123
  0      0

What is the least number of moves necessary to transfer the keys of the first arrangement into the other arrangement?
One move consists of switching the position of two neighbouring keys (Horizontal, vertical or diagonal) of which the sum is 9, 10 or 11.
Example: In the starting position you can switch 6 and 3, 5 and 6, 4 and 5, 7 and 4, 0 and 9

well, I think it's an uninterresting problem because the only thing involved here is finding the quickest way by trying or a little more. But there is no wow idea to use for solving this one 

Posted by traian on 2005-07-07 14:33:18