sol06a.erl

#!/usr/bin/escript

main([]) ->
	main(["sol06.data"]);
main([Filename]) ->
	{ok, File} = file:open(Filename, [read]),
	Data = parse_file(File),
	file:close(File),
	Counts = [count_answers(G) || G <- Data],
	Total = lists:foldl(fun erlang:'+'/2, 0, Counts),
	io:format("~B~n", [Total]).


parse_file(File) ->
	parse_line(File, read_line(File), [[]]).

parse_line(_File, eof, Acc) ->
	Acc;
parse_line(File, "", Acc) ->
	parse_line(File, read_line(File), [[]|Acc]);
parse_line(File, Line, [First | Rest]) ->
	parse_line(File, read_line(File), [[Line | First] | Rest]).

read_line(File) ->
	case file:read_line(File) of
		{ok, Line} ->
			string:chomp(Line);
		Other ->
			Other
	end.

count_answers(Group) ->
	All = lists:usort(lists:append(Group)),
	length(All).