-1

An antisnap pack of cards has no cards the same type one after another. You have say 10 sets of 10 different cards together sequentially- 10 of Type 1, 10 of Type 2.... What is the most efficient way (with the least number of intermediate piles of cards produc and cards moved) of producing a set of cards such other the antisnap condition it is random with generally every pack different? We do this sort of problem at work at the time.

user2617804
  • 219
  • 1
  • 7

1 Answers1

2

One possibility is to first divide the cards into two equally-sized piles with all the cards of any given type going into the same pile. So one pile consists of say, types 1-5 and the other consists of types 6-10. Shuffle each pile individually however you like, and then interleave the two to get the final deck. This last step can be performed quickly if you're skilled at doing a perfect Faro shuffle, assuming your cards have the right size and flexibility like playing cards.

Of course this method can't give you every possible permutation, since half the types will always appear in the odd positions and the other half in the even positions. Whether this amount of randomness is acceptable we can't say without knowing more details.

Carmeister
  • 2,205
  • 11
  • 16
  • Good answer, but 100 cards might be a bit unwieldy for the perfect riffle shuffle. – Weather Vane Jul 22 '23 at 19:52
  • Admittedly I can't do it myself, so I don't have a good notion of how difficult it is. If 100 is too many you could divide the piles in half and separately interleave the top and bottom halves of each. – Carmeister Jul 22 '23 at 20:03
  • How does this produce an antisnap pile- the absolute requirement? – user2617804 Jul 22 '23 at 23:44
  • 1
    @user2617804 For the reason described in the last paragraph - initially each type appears in only one of the two piles, so after interleaving it will appear in only odd or only even positions. Therefore no two cards of the same type can be consecutive. – Carmeister Jul 22 '23 at 23:46