Top- Based Adaptive Enumeration in Constraint Programming

Algorithm 6

sudokusolve(ProblemName):-

 problem(ProblemName, Board),

 sudoku(3, Board).

sudoku(N, Board):-

 N2 is N*N,

 dim(Board, N2,N2),

 Board1..N2,1..N2  :: 1..N2,

 ( for(I,1,N2), param(Board,N2) do

  Row is BoardI,1..N2,

  alldifferent(Row),

  Col is Board1..N2,I,

  alldifferent(Col)

 ),

 ( multifor(I,J,1,N2,N), param(Board,N) do

  ( multifor(K,L,0,N-1), param(Board,I,J),

   foreach(X,SubSquare) do

    X is BoardI+K,J+L

  ),

  alldifferent(SubSquare)

 ),

 term_variables(Board, Vars),

  % call to search predicate

 write(Board).

problem(1, (

 (_, _, 2, _, _, 5, _, 7, 9),

 (1, _, 5, _, _, 3, _, _, _),

 (_, _, _, _, _, _, 6, _, _),

 (_, 1, _, 4, _, _, 9, _, _),

 (_, 9, _, _, _, _, _, 8, _),

 (_, _, 4, _, _, 9, _, 1, _),

 (_, _, 9, _, _, _, _, _, _),

 (_, _, _, 1, _, _, 3, _, 6),

 (6, 8, _, 3, _, _, 4, _, _))).