% Magic sequence in MiniZinc.
% Alternative version which use the global constraint distribute.
% See magic_sequence.mzn, magic_sequence2.mzn.
% A magic sequence of length n is a sequence of integers x0 . . xn-1 between 0 and n-1, such that for all i in 0 to n-1, the number i occurs exactly xi times in the sequence. For instance, 6,2,1,0,0,0,1,0,0,0 is a magic sequence since 0 occurs 6 times in it, 1 occurs twice, ...
% Model created by Hakan Kjellerstrand, firstname.lastname@example.org
% See also my MiniZinc page: http://www.hakank.org/minizinc
% Licenced under CC-BY-4.0 : http://creativecommons.org/licenses/by/4.0/
int: n = 10;
array[0..n-1] of var 0..n-1: s;
array[0..n-1] of int: value = array1d(0..n-1, [i | i in 0..n-1]); % helper for distribute
% solve satisfy;
solve :: int_search(s, first_fail, indomain_min, complete) satisfy;
distribute(s, value, s) /\
sum(i in 0..n-1) (s[i]) = n /\
sum(i in 0..n-1) (s[i]*i) = n