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 2020-11-24, 07:13 #1 sticky   Nov 2020 416 Posts Number with all permutations between any 2 digits Lets say you are given a set of n consecutive digits , Ex {0,1,2,3}. You are required to form a number using the digits which abides by the following rule: 1.The number should cover all relations (ex 12 and 21) between any 2 digits from the set of numbers For the given set this number would be :0123130203210 or 0123021310320. I was able to get this number manually by trial and error. Is there a deterministic way of achieving this number for any n consecutive digits? The number will have all the 2 digit permutations only once. 0 -> [1,2,3] will yield 01 , 02 , 03 1 -> [0,2,3] will yield 10 , 12 , 13 2 -> [0,1,3] will yield 20 , 21 , 23 3 -> [0,1,2] will yield 30 , 31 , 32 We have to generate a number which will cover all the above relations. Last fiddled with by sticky on 2020-11-24 at 08:04
 2020-11-24, 10:14 #2 LaurV Romulan Interpreter     "name field" Jun 2011 Thailand 1027310 Posts Why can't you just list all C(n,2) in a row lexicografic and add a zero at the end? 0102031213230 This is deterministic and correct (can you prove?).
 2020-11-24, 13:24 #3 Viliam Furik     "Viliam Furík" Jul 2018 Martin, Slovakia 11000110002 Posts I think what you are looking for is the Superpermutation page on Wikipedia.
 2020-11-24, 13:44 #4 Dr Sardonicus     Feb 2017 Nowhere 7×887 Posts 1) It occurred to me to wonder whether this might be a homework problem. 2) IMO this is not "superpermutations." For the problem as described, the the "list all transpositions" approach seems to be appropriate. A concept related, but not directly related to this problem, is that of a transitive group.
 2020-11-24, 17:12 #5 sticky   Nov 2020 22 Posts The answer is Eulerian path. Algorithm is Hierholzers path detection.
2020-11-24, 17:21   #6
Viliam Furik

"Viliam Furík"
Jul 2018
Martin, Slovakia

23·32·11 Posts

Quote:
 Originally Posted by Dr Sardonicus 2) IMO this is not "superpermutations."
Yes, but it's something like generalized superpermutations, with generalization being the fact that they consist of permutations of combinations of the symbols. So kind of like "Combinational superpermutations".

The example, 0123021310320, contains every permutation of every two-element combination of the 4 elements - {0;1;2;3}.

 2020-11-25, 03:58 #7 MattcAnderson     "Matthew Anderson" Dec 2010 Oregon, USA 119110 Posts I didn't quite understand the question, but I believe the Alternating group is relevant. Briefly it is the set of all even number of transpositions. see Wikipedia Alternating group. Regards, Matt

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