Túm lại:

n = red hats; m= blue hats = players; n = m - 1.
c = actual red hats in front; p = max possibility red hats ỉn front.

if c = p -> current player wears blue hat. Done.
else: next player's p = current p - 1.

Mai mốt đại hội VCF, kéo 101 ace ra chơi thử :-)