PS. There is also an idea for solving puzzle 130. It may be stupid, but I’ll suggest it anyway. What if made check on the server side the distance between the every tame and every wild kangaroos?
And check the result with a hashtable like on BSGS. I don’t know how likely it is that the distance between the some Tame/Wild kangaroos would be less than the size of the table, but nevertheless as soon as the difference is known, the key will be found.
You can't check the distance between a tame and wild because that would mean you already know the answer to the problem. The wild distance is relative to the unknown position of the public key.