The array below represents a set of 16 playing cards, with the A's representing Aces:
A 5 5 A
5 2 4 10
3 8 7 4
A A 2 6
Divide the array into sections of adjacent cards so that the sum of the cards' values in each section will be 21. Each Ace can represent either 1 or 11 and you must determine how many sections are needed.
From PageaDay Calendar 2016: Amazing Mind Benders, by Puzzability (Mike Shenk, Amy Goldstein and Robert Leighton), Workman Publishing, NY; puzzle for August 6,7.
(In reply to
Full solution  SPOILER by Ady TZIDON)
I assume the special characters were to tie together members of a group. I should have mentioned, I guess, that meeting at a corner doesn't make the cards adjacent: they must share a common side. In your * group, the 2 and 3 meet at only a corner.

Posted by Charlie
on 20160811 09:06:28 