080: Blocked n-Queens Problem

language ESSENCE' 1.0
given      n : int(1..)
letting    AMOUNT_QUEENS be domain int(0..n-1)
given      blocks : matrix indexed by [ int(1..given_queens), int(1..2) ] of int(1..n)
find       q1: matrix indexed by [ AMOUNT_QUEENS ] of int(0..n-1)
find       q2: matrix indexed by [ AMOUNT_QUEENS ] of int(-(n-1)..n-1)
find       q3: matrix indexed by [ AMOUNT_QUEENS ] of int(0..(n-1)*2)


such that  allDiff(q1), 
           allDiff(q2), 
           allDiff(q3),
           
         $ diagonals
           forAll i : AMOUNT_QUEENS . (
               table([q2[i], q1[i]], [[a,a+i] | a : int(-(n-1)..n-1), a+i>=0, a+i<n])  /\
               table([q3[i], q1[i]], [[a,a-i] | a : int(0..(n-1)*2), a-i>=0, a-i<n])
           ),

           forAll i : int(1..given_queens) .
               (q1[blocks[i,1]-1] != blocks[i,2]-1),
           
        true