Magic_Sequence.mzn

include "count.mzn";
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% PARAMETERS        
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% Length of the sequence
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int: n;
set of int: Indexes = 0..n-1;
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% VARIABLES        
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% The sequence itself
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array[Indexes] of var int: magic;

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% Constraints 
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% Tips:                                 
% - sum(array) return sum of the array's elements 
% - you can use bool's like integers
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%constraint forall(i in Indexes) (magic[i] = (sum(j in Indexes)(bool2int(magic[j]=i))));
constraint forall(i in Indexes)(count(magic, i, magic[i]));
    
solve satisfy;
  
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% EXAMPLE OUTPUT  
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% - magic - magic sequence     
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output [ "magic sequence = ", show(magic),";\n"];