Same problem twice?

[fletch]

Hi,

I'm a new user of the site - really enjoying the puzzles.

I've just got one question - I'm not sure how many problems there are or  what your algorithms are like for choosing them but I just got given exactly the same puzzle twice in a minute... was good for my rating as I solved quickly second time round - but I guess I'd prefer different ones if possible...

Matt

[richard]

Hi fletch,

This shouldn't happen very often but it certainly will happen occasionally  over time.  Let me know if this seems to be happening a lot for you.

Thanks,
Richard.

[fletch]

Hi Richard,

It hasn't happened for a while but I just got two in very quick succession:

06/11/2007 23:35   1339   2162   blitz   8   2444(   47
06/11/2007 23:38   1339   2147   blitz   13   2442(2)   46

06/11/2007 23:38   8520   1983   blitz   5   2444(7)   46
06/11/2007 23:42   8520   1979   blitz   11   2454(6)   44

There were about 6 problems between the first two and about 10 problems between the second two.  Not a big issue but if there was anything you could do about it that would be great...

Thanks

Matt

[richard]

Its a bit unusual but not completely out of expectations to have a few duplicates like that. Remember that even if you have 10000 problems in the system the chances of getting a duplicate is not 1 in 10000 but much higher due to problems being biased towards those close to your rating.

Regards,
Richard.

[roq]

Yesterday I had a quite low rated problem that completely stumped me - after 4 minutes I gave up. However, when I saw the solution, i realised i had solved it instantly a bit earlier...

I think perhaps we learn tactics a bit like Skinner's pigeons or Pavlov's dogs so some repetition is probably good.