要求创建对角线数独板 EN！

:-use_module(library(clpfd)).          % Constraint Programming Library

a(R):-                                 % Main Predicate
    l(9,R),m(l(9),R),append(R,V),      % R is a list of 9 lists, each of length 9
    V ins 1..9,                        % Values in R are between 1 and 9
    transpose(R,C),                    % C is the transpose of R
    d(0,R,D),                          % D is the diagonal of R
    maplist(reverse,R,S),d(0,S,E),     % E is the anti-diagonal of R
    r(R),                              % All 3*3 blocks must contain numbers from 1 to 9
    m(m(all_distinct),[R,C,[D,E]]),    % Each row of R, each row of C, D and E must contain
                                       % only distinct numbers
    get_time(I),J is ceil(I),          % Set J to a random number based on the current time
    m(labeling([random_value(J)]),R).  % Randomly find a solution for R

l(L,M):-                               % L is the length of M
    length(M,L).

r([A,B,C|T]):-                         % For each group of 3 rows, the 3*3 blocks must
    b(A,B,C),r(T);!.                   % contain distinct numbers

b([A,B,C|X],[D,E,F|Y],[G,H,I|Z]):-     % Checks that the 3 3*3 blocks of 3 rows have
                                       % distinct numbers inside them
    all_distinct([A,B,C,D,E,F,G,H,I]),
    b(X,Y,Z);!.

d(X,[H|R],[A|Z]):-                     % [A|Z] is the diagonal of [H|R]
    nth0(X,H,A),
    Y is X+1,
    (R=[],Z=R;d(Y,R,Z)).

m(A,B):-
    maplist(A,B).