Enigma 1058: A row of colours
11 June 2018
Posted by on
From New Scientist #2214, 27th November 1999 [link]
Pusicatto has been asked by a family to paint a picture consisting of a row of squares, which each square either red or green. Each member of the family has expressed a wish for something they would like to appear in the picture. For example, Mum asked for G??R?G, by which she meant that, somewhere in the row, there should be a green square, then two squares that could be of either colour, then a red square, then a square of either colour, and then a green square, without any other squares coming between them. Dad asked for G?R?R. The children’s requests were:
Pusicatto decided to paint the picture so that it had the smallest number of squares possible.
What was the order of the squares in Pusicatto’s painting?