numbers_strings([], []).
numbers_strings([A|As], [B|Bs]) :-
    number_string(A, B),
    numbers_strings(As, Bs).

read_file(Stream, X) :-
    \+ at_end_of_stream(Stream),
    read_line_to_codes(Stream, C),
    string_chars(S, C),
    split_string(S, ",", "", Y),
    numbers_strings(X, Y),
    at_end_of_stream(Stream).

main :-
    open('../input/07', read, Stream),
    read_file(Stream, Lines), !,
    close(Stream),
    msort(Lines, L),
    length(L, Len),
    I is Len // 2,
    nth0(I, L, X),
    calculate_diff(L, X, N),
    print([X, N]).

calculate_diff([], _, 0).
calculate_diff([A|As], X, B) :-
    calculate_diff(As, X, B0),
    B is B0 + abs(A - X).