day 3 prolog

pl/03.1.pl

@@ -0,0 +1,63 @@
+chars_digits([], []).
+chars_digits([C|Cs], [D|Ds]) :-
+    char_type(C, digit(D)),
+    chars_digits(Cs, Ds).
+
+read_file(Stream, []) :-
+    at_end_of_stream(Stream).
+read_file(Stream, [X|L]) :-
+    \+ at_end_of_stream(Stream),
+    read_line_to_codes(Stream, C),
+    chars_digits(C, X),
+    read_file(Stream, L).
+
+main :-
+    open('../input/03', read, Stream),
+    read_file(Stream, Lines), !,
+    close(Stream),
+    solve(Lines, A, B),
+    bin_dec(A, A1),
+    bin_dec(B, B1),
+    X is A1 * B1,
+    print([A1, B1, X]).
+
+list_sum([], [], []).
+list_sum([A|As], [B|Bs], [C|Cs]) :-
+    list_sum(As, Bs, Cs),
+    C is A + B.
+listlist_sum([], C, C).
+listlist_sum([A|As], I, C) :-
+    list_sum(A, I, I1),
+    listlist_sum(As, I1, C).
+
+zerolist([], []).
+zerolist([_|As], [0|Bs]) :-
+    zerolist(As, Bs).
+
+listlist_sum([A|As], Sum) :-
+    zerolist(A, B),
+    listlist_sum([A|As], B, Sum).
+
+div([], _, []).
+div([A|As], N, [B|Bs]) :-
+    B is A // N,
+    div(As, N, Bs).
+
+neg([], []).
+neg([A|As], [B|Bs]) :-
+    B is 1 - A,
+    neg(As, Bs).
+
+solve(Lines, Res1, Res2) :-
+    listlist_sum(Lines, Sum),
+    length(Lines, Len),
+    div(Sum, Len // 2, Res1),
+    neg(Res1, Res2).
+
+bin_dec(B, X) :-
+    bin_dec(B, 0, X).
+bin_dec([], X, X).
+bin_dec([B|Bs], N, X) :-
+    M is N * 2 + B,
+    bin_dec(Bs, M, X).
+

pl/03.2.pl

@@ -0,0 +1,89 @@
+chars_digits([], []).
+chars_digits([C|Cs], [D|Ds]) :-
+    char_type(C, digit(D)),
+    chars_digits(Cs, Ds).
+
+read_file(Stream, []) :-
+    at_end_of_stream(Stream).
+read_file(Stream, [X|L]) :-
+    \+ at_end_of_stream(Stream),
+    read_line_to_codes(Stream, C),
+    chars_digits(C, X),
+    read_file(Stream, L).
+
+main :-
+    open('../input/03', read, Stream),
+    read_file(Stream, Lines), !,
+    close(Stream),
+    most_solve(Lines, A),
+    least_solve(Lines, B),
+    bin_dec(A, A1),
+    bin_dec(B, B1),
+    X is A1 * B1,
+    print([A1, B1, X]).
+
+first_elements([], []).
+first_elements([[X|_]|As], [B|Bs]) :-
+    first_elements(As, Bs),
+    B is X.
+last_elements([], _, []).
+last_elements([[X|Xs]|As], X, [Xs|Bs]) :-
+    last_elements(As, X, Bs).
+last_elements([[X|_]|As], F, Bs) :-
+    F =\= X,
+    last_elements(As, F, Bs).
+
+freq([], 0, 0).
+freq([1|As], Z, O) :-
+    freq(As, Z, O1),
+    O is O1 + 1.
+freq([0|As], Z, O) :-
+    freq(As, Z1, O),
+    Z is Z1 + 1.
+ 
+most_common(A, 1) :-
+    freq(A, Z, O),
+    O >= Z.
+most_common(A, 0) :-
+    freq(A, Z, O),
+    O < Z.
+least_common(A, 0) :-
+    freq(A, Z, O),
+    Z > 0,
+    (O >= Z; O = 0).
+least_common(A, 1) :-
+    freq(A, Z, O),
+    O > 0,
+    (O < Z; Z = 0).
+
+first_elem([A|_], A).
+
+most_solve(A, [B]) :-
+    first_elements(A, F),
+    most_common(F, B),
+    first_elem(A, N),
+    length(N, 1).
+most_solve(A, [B|Bs]) :-
+    first_elements(A, F),
+    most_common(F, B),
+    last_elements(A, B, L),
+    most_solve(L, Bs).
+
+least_solve(A, [B]) :-
+    first_elements(A, F),
+    least_common(F, B),
+    first_elem(A, N),
+    length(N, 1).
+least_solve(A, [B|Bs]) :-
+    first_elements(A, F),
+    least_common(F, B),
+    last_elements(A, B, L),
+    least_solve(L, Bs).
+
+bin_dec(B, X) :-
+    bin_dec(B, 0, X).
+bin_dec([], X, X).
+bin_dec([B|Bs], N, X) :-
+    M is N * 2 + B,
+    bin_dec(Bs, M, X).
+