Hi Vlad,
>2. The smurfs solve it in the second day. This means there are 2 reds because there are at least 2 and the red ones can see that there are at most 2, etc. But they don't solve it in the 2nd day, so, there are at least 3.
OK, this would mean that each smurf must go to the king after x+1 days where x is the number of hats he sees. So if a smurf sees 12 green hats, he must go to the king on day 13. If he has a green hat, then all green smurf would meet on day 13. And if he has a red hat, all green smurfs would have met on day 12, because they could only see 11 green smurfs. And the red one would be just in time for the meeting of red smurfs.
Did I get it?
Christof
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Christof