include "alldifferent.mzn"; int: n; array[1..n] of var 1..n: y; % position of each number array[1..n-1] of var 1..n-1: v; % position of difference i constraint alldifferent(y); constraint alldifferent(v); constraint forall(i,j in 1..n where i < j)( (y[i] - y[j] = 1 -> v[j-i] = y[j]) /\ (y[j] - y[i] = 1 -> v[j-i] = y[i]) ); constraint abs(y[1] - y[n]) = 1 /\ v[n-1] = min(y[1], y[n]); solve :: int_search(y, first_fail, indomain_min) satisfy; array[1..n] of 1..n: x :: output_only = [ sum(i in 1..n)(i*(fix(y[j]) = i) | j in 1..n ]; output [ "x = \(x);\n" ]