alan day5 and day6

day6/day6.erl

@@ -0,0 +1,73 @@
+%% to compile: erlc day3A.erl
+%% to run: erl -noshell -s day5 solve
+%%
+-module(day6).
+
+-export ([solve/0, solve/1, solve/2]).
+-export ([read_input/0]).
+
+solve() ->
+    solve(['1']),
+    solve(['2']),
+    init:stop().
+
+solve(A) ->
+    solve(A, read_input()).
+
+solve(['1'], D) ->
+    io:format("The solution to ~p puzzle1 is: ~p~n", [?MODULE, solve(1, D)]);
+solve(1, D) ->
+    solution1(D);
+solve(['2'], D) ->
+    io:format("The solution to ~p puzzle2 is: ~p~n", [?MODULE, solve(2, D)]);
+solve(2, D) ->
+    solution2(D).
+
+read_input() ->
+    {ok, IO} = file:open("input.txt", 'read'),
+    Data = read_input(IO),
+    file:close(IO),
+    Data.
+
+read_input(IO) ->
+    read_line(IO).
+
+read_line(IO) ->
+    case file:read_line(IO) of
+        'eof' -> 'eof';
+        {ok, Line} -> parse_line(Line)
+    end.
+
+parse_line(Line) ->
+    Points = string:tokens(Line, " ,->\n"),
+    parse_line([list_to_integer(X) || X <- Points], [{0,0},{1,0},{2,0},{3,0},{4,0},{5,0},{6,0},{7,0},{8,0}]).
+
+parse_line([], Acc) ->
+	io:format("input: ~p~n", [Acc]),
+	Acc;
+parse_line([H|T], Acc) ->
+    {A, V} = lists:keyfind(H, 1, Acc),
+    parse_line(T, lists:keyreplace(H, 1, Acc, {A, V + 1})).
+
+solution1(Input) ->
+    Fish =  days(Input, 80),
+    io:format("OUT: ~p~n", [Fish]),
+    lists:foldl(fun({_A, V}, Acc) -> Acc + V end, 0, Fish).
+solution2(Input) ->
+    Fish =  days(Input, 256),
+    io:format("OUT: ~p~n", [Fish]),
+    lists:foldl(fun({_A, V}, Acc) -> Acc + V end, 0, Fish).
+days(Input, 0) ->
+	Input;
+days(Input, Count) ->
+    New  = 
+    lists:foldl(fun({A, V}, AccIn) -> 
+	case A of 
+	    0 -> 
+	 	{7, V1} = lists:keyfind(7, 1, Input),
+		AccIn ++ [{6, V + V1},{8, V}];
+            7 -> AccIn;
+	    _ -> AccIn ++ [{A-1, V}]
+	end
+    	end, [], Input),
+    days(New, Count -1).