diff --git a/day10/input.txt.test b/day10/input.txt.test
deleted file mode 100644
index b1518d9..0000000
--- a/day10/input.txt.test
+++ /dev/null
@@ -1,10 +0,0 @@
-[({(<(())[]>[[{[]{<()<>>
-[(()[<>])]({[<{<<[]>>(
-{([(<{}[<>[]}>{[]{[(<()>
-(((({<>}<{<{<>}{[]{[]{}
-[[<[([]))<([[{}[[()]]]
-[{[{({}]{}}([{[{{{}}([]
-{<[[]]>}<{[{[{[]{()[[[]
-[<(<(<(<{}))><([]([]()
-<{([([[(<>()){}]>(<<{{
-<{([{{}}[<[[[<>{}]]]>[]]
diff --git a/day17/day17.erl b/day17/day17.erl
new file mode 100644
index 0000000..f887a61
--- /dev/null
+++ b/day17/day17.erl
@@ -0,0 +1,68 @@
+%% to compile: erlc day3A.erl
+%% to run: erl -noshell -s day5 solve
+%%
+-module(day17).
+
+-export ([solve/0, solve/1, solve/2]).
+-compile ([export_all]).
+
+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).
+
+solution1({X,Y}) ->
+    Xs = find_x(X),
+    Ys = find_y(Y),
+    {T, X1, Y1} = lists:max([{Key, X1, proplists:get_value(Key,Ys)} || {Key, X1} <- Xs, lists:keysearch(Key, 1, Ys) /= false]),
+    y_max(T,Y1,0).
+    
+solution2({X,Y}) ->
+    Xs = find_x(X),
+    Ys = find_y(Y),
+    length(lists:usort([{X,Y} || {Ty, Y} <- Ys, {T,X} <- lists:filter(fun({T,X}) -> T == Ty end, Xs)])).
+
+read_input() ->
+    {{124,174},{-123, -86}}.
+%%    {{20,30},{-10, -5}}.
+
+find_x({Xmin, Xmax}) ->
+    [ {T, Xstart}  || Xstart <- lists:seq(0,400), T <- lists:seq(1,1000),  x(Xstart, T) >= Xmin, x(Xstart, T) =< Xmax ].
+
+find_y({Ymin, Ymax}) ->
+    [ {T, Ystart}  || Ystart <- lists:seq(-400,400), T <- lists:seq(1,1000), y(Ystart, T) >= Ymin, y(Ystart, T) =< Ymax ].
+
+x(Xstart, T) ->
+    Last = 
+    case (Xstart - T + 1) of
+        L when L < 0 -> 0;
+        L -> L
+    end,
+    (Xstart - Last + 1) * (Xstart + Last) div 2.
+   
+y(Ystart, T) ->
+    Last = (Ystart - T + 1),
+    (Ystart - Last + 1) * (Ystart + Last) div 2.
+
+y_max(0, _, Ymax) -> Ymax;
+y_max(T, Y, Ymax)  ->
+    NewY = y(Y, T),
+    NewMax = 
+    case  NewY of
+        M when M > Ymax -> M;
+        _ -> Ymax
+    end,
+    y_max(T-1, Y, NewMax).
+    
\ No newline at end of file
diff --git a/day17/diagram.txt b/day17/diagram.txt
new file mode 100644
index 0000000..845b9a9
--- /dev/null
+++ b/day17/diagram.txt
@@ -0,0 +1,26 @@
+              1         2         3
+4   0123456789012345678901234567890
+3   .............#....#............
+2   .......#..............#........
+1   ...............................
+0   S........................#.....
+-1  ...............................
+-2  ...............................
+-3  ...........................#...
+-4  ...............................
+-5  ....................TTTTTTTTTTT
+-6  ....................TTTTTTTTTTT
+-7  ....................TTTTTTTT#TT
+-8  ....................TTTTTTTTTTT
+-9  ....................TTTTTTTTTTT
+-10 ....................TTTTTTTTTTT
+
+T X y
+0 0 0     = 0
+1 7  +6   = 7
+2 13 +5   = 7 + 6
+3 18 +4   = 7 + 6 + 5
+4 22 +3   = 7 + 6 + 5 + 4
+5 25 +2
+6 27 +1
+7 28 +0
\ No newline at end of file
diff --git a/day17/input.txt b/day17/input.txt
new file mode 100644
index 0000000..ac12128
--- /dev/null
+++ b/day17/input.txt
@@ -0,0 +1 @@
+target area: x=124..174, y=-123..-86
\ No newline at end of file
diff --git a/day18/day18.erl b/day18/day18.erl
new file mode 100644
index 0000000..cc4223c
--- /dev/null
+++ b/day18/day18.erl
@@ -0,0 +1,130 @@
+-module(day18).
+
+-export ([solve/0, solve/1]).
+-compile ([export_all]).
+
+solve() ->
+    solve(['1']),
+    solve(['2']),
+    init:stop().
+
+solve(['1']) ->
+    io:format("The solution to ~p puzzle1 is: ~p~n", [?MODULE, solve(1)]);
+solve(1) ->
+    solution1();
+solve(['2']) ->
+    io:format("The solution to ~p puzzle2 is: ~p~n", [?MODULE, solve(2)]);
+solve(2) ->
+    solution2().
+
+solution1() ->
+    {ok, IO} = file:open("input.txt", 'read'),
+    Ans = maybe_reduce(read_line(IO), IO),
+    file:close(IO),
+    magnitude(Ans).
+    
+solution2() ->
+    {ok, IO} = file:open("input.txt", 'read'),
+    Numbers = read_all_lines(read_line(IO), IO, []),
+    file:close(IO),
+    io:format("total:~p lines: ~p~n", [length(Numbers), Numbers]),
+    max_magnitude(Numbers).
+
+read_all_lines('eof', _IO, Acc) ->
+    Acc;
+read_all_lines(Line, IO, Acc) ->
+    read_all_lines(read_line(IO), IO, [Line|Acc]).
+
+read_line(IO) ->
+    case file:read_line(IO) of
+        {ok, Line} ->
+            {ok, Tokens, _} = erl_scan:string(Line ++ "."),
+            {ok, Term} = erl_parse:parse_term(Tokens),
+            Term;
+        'eof' -> 'eof'
+    end.
+
+max_magnitude(Numbers) when is_list(Numbers) ->
+    lists:max([ max_magnitude(lists:split(I, Numbers)) || I <- lists:seq(1, length(Numbers))]);
+max_magnitude({List1, List2}) ->
+    [H|T] = lists:reverse(List1),
+    max_magnitude(H, T ++ List2).
+
+max_magnitude(Number, Rest) -> 
+    lists:foldl(fun(N, MaxMag) ->
+        case magnitude(reduce([Number, N])) of
+            Mag  when Mag > MaxMag -> Mag;
+            _ -> MaxMag
+        end
+        end, 0, Rest).
+    
+
+magnitude(A) when is_integer(A) -> A;
+magnitude([A,B]) ->
+    (3 * magnitude(A)) + (2 * magnitude(B)).
+
+maybe_reduce(A, IO) ->
+    case read_line(IO) of
+        'eof' -> A;
+        B ->
+            maybe_reduce(reduce([A,B]), IO)
+    end.
+
+reduce(N) ->
+    case maybe_explode(N, 0) of
+        {true, New, _, _} ->
+            reduce(New);
+        false ->
+            case maybe_split(N) of
+                {true, New} ->
+                    reduce(New);
+                false ->
+                    N
+            end
+    end.
+
+maybe_explode([A,B], Depth) when Depth >= 4, is_integer(A), is_integer(B) ->
+    {true, 0, A, B};
+maybe_explode([A,B], Depth) ->
+    case maybe_explode(A, Depth+1) of
+        {true, New, AddA, AddB} ->
+            {true, [New, add_explode({b, AddB}, B)], AddA, 0};
+        false ->
+            case maybe_explode(B, Depth+1) of
+                {true, New, AddA, AddB} ->
+                    {true, [add_explode({a, AddA}, A), New], 0, AddB};
+                false ->
+                    false
+            end
+    end;
+maybe_explode(N, _) when is_integer(N) ->
+    false.
+
+add_explode({_, Add}, Num) when is_integer(Num) ->
+    Add + Num;
+add_explode({b, Add}, [A,B]) ->
+    [add_explode({b, Add}, A), B];
+add_explode({a, Add}, [A,B]) ->
+    [A, add_explode({a,Add}, B)].
+
+maybe_split(N) when is_integer(N) ->
+    case N > 9 of
+        true ->
+            Left = N div 2,
+            Right = case Left*2 == N of true -> Left; false -> Left+1 end,
+            {true, [Left, Right]};
+        false ->
+            false
+    end;
+maybe_split([A, B]) ->
+    case maybe_split(A) of
+        {true, NewA} ->
+            {true, [NewA, B]};
+        false ->
+            case maybe_split(B) of
+                {true, NewB} ->
+                    {true, [A, NewB]};
+                false ->
+                    false
+            end
+    end.
\ No newline at end of file
diff --git a/day18/input.txt b/day18/input.txt
new file mode 100644
index 0000000..a49398e
--- /dev/null
+++ b/day18/input.txt
@@ -0,0 +1,100 @@
+[[[9,2],[[2,9],0]],[1,[[2,3],0]]]
+[[[[2,0],2],[[6,4],[7,3]]],[0,[[3,0],[0,6]]]]
+[[[[7,2],2],[9,[6,5]]],[[2,4],5]]
+[[[[7,8],2],1],[[[5,4],[2,9]],[7,8]]]
+[[[0,7],[1,[6,6]]],[[[0,7],9],4]]
+[[[3,[9,6]],[5,1]],[[[0,1],6],[[7,6],0]]]
+[[[3,0],[7,[4,0]]],[4,[[6,6],[5,3]]]]
+[[[1,[4,8]],[2,[5,8]]],[[[3,6],[2,2]],[[3,8],[7,0]]]]
+[9,[[[5,0],[0,3]],[2,[2,6]]]]
+[[[3,[8,2]],[[8,0],5]],[[[7,6],[4,9]],[7,5]]]
+[[7,[[4,1],9]],[5,1]]
+[[[5,[7,5]],1],[8,[5,8]]]
+[[[[0,2],7],[[1,4],[9,8]]],[[3,[0,3]],7]]
+[[[[4,3],[7,4]],[6,[6,4]]],[8,0]]
+[[[1,1],1],[[5,[2,7]],7]]
+[[[5,4],5],[[7,[6,3]],[[8,4],6]]]
+[[[7,9],[[4,4],[0,0]]],[[[8,6],6],[2,[6,4]]]]
+[[[[4,7],[4,9]],3],[[[7,1],[8,6]],[9,[8,2]]]]
+[6,[6,[2,9]]]
+[[4,[[5,5],[5,0]]],[[[3,4],[9,5]],[8,6]]]
+[2,[0,[2,5]]]
+[[[4,[7,1]],[2,8]],[[7,0],[[1,6],1]]]
+[[[3,4],[[7,8],[6,7]]],[[[6,2],[1,2]],5]]
+[[[8,[0,8]],[[9,9],0]],[[[3,5],[4,2]],7]]
+[[0,[[0,3],2]],[4,1]]
+[[[[0,4],6],7],[[4,[9,1]],3]]
+[[0,[[7,0],8]],[2,[8,[8,2]]]]
+[[[[3,6],2],[9,4]],[6,[[7,9],[4,5]]]]
+[[[[4,9],1],[[9,6],[8,8]]],[[7,[7,6]],[[8,3],[9,0]]]]
+[2,0]
+[[[[8,2],0],[3,5]],[[7,2],0]]
+[[[[1,9],9],6],[9,[[9,3],[8,7]]]]
+[[[9,[4,0]],[[7,1],[4,4]]],[[4,[2,3]],[8,7]]]
+[[[[9,7],[5,6]],[4,[6,7]]],7]
+[5,[[[8,2],8],[6,[7,9]]]]
+[0,[[9,[0,1]],[[8,3],7]]]
+[[[[4,5],[4,2]],[[5,2],[3,1]]],[[[3,1],[8,5]],8]]
+[[0,4],[[2,[2,6]],[[1,1],3]]]
+[[[0,8],[7,[5,8]]],7]
+[[[7,2],[[6,6],[2,7]]],[[0,[9,3]],2]]
+[[[[0,9],2],[[6,0],4]],3]
+[[5,[[9,6],9]],[[6,[1,2]],[1,[6,2]]]]
+[[[[3,9],5],[9,[7,2]]],[5,[[3,4],[0,6]]]]
+[[2,[6,7]],[0,[[2,0],7]]]
+[[2,[[5,4],[2,1]]],[2,[[8,7],[5,3]]]]
+[[[[0,4],[2,5]],[1,2]],[5,[8,[0,3]]]]
+[[[[9,2],[3,2]],[[2,9],4]],5]
+[[[[8,9],5],1],[9,3]]
+[[5,2],[3,[[8,5],2]]]
+[[[0,1],[7,8]],[[[6,2],4],[[6,2],[9,5]]]]
+[[[[9,6],5],2],2]
+[[[[3,2],3],3],[[[0,1],1],[[8,4],8]]]
+[[4,[2,[3,0]]],[[6,[7,0]],6]]
+[[6,[[7,8],3]],[[[2,7],4],9]]
+[0,2]
+[[[9,1],[[3,7],[6,0]]],[[0,[4,1]],[[5,4],7]]]
+[[[3,[9,4]],8],[[5,3],2]]
+[[6,6],[[[0,5],[0,9]],[[5,5],4]]]
+[[[[1,2],4],[[2,4],[8,0]]],[0,[[4,4],[5,8]]]]
+[0,[[[9,0],3],[8,4]]]
+[[4,5],[[[9,9],[3,5]],[8,[1,4]]]]
+[[7,8],[[[3,1],[7,0]],[[4,7],[9,1]]]]
+[[4,[2,[1,9]]],[[6,[6,1]],[[0,3],3]]]
+[[[5,[0,9]],6],[[[3,4],[9,6]],[[4,0],[0,4]]]]
+[[[1,5],[8,[2,8]]],[[5,[0,8]],[[0,7],[4,6]]]]
+[[9,[0,2]],[[3,3],[3,1]]]
+[[[[2,8],[5,9]],[2,[1,5]]],9]
+[[3,[[8,9],[3,1]]],[[[9,0],7],[[0,4],3]]]
+[[[[1,5],2],[5,[5,9]]],[5,[[0,1],[0,2]]]]
+[6,[[[0,4],8],[[8,2],[5,5]]]]
+[[[[7,7],5],[[8,2],7]],[2,5]]
+[[[1,1],[[7,8],0]],3]
+[[6,[[4,2],9]],[[[5,4],4],3]]
+[[[[5,8],3],[[0,4],9]],[[[2,9],2],[3,4]]]
+[[0,[4,8]],6]
+[[[[9,5],[1,9]],[[3,7],[5,5]]],8]
+[[1,9],6]
+[[[4,[1,5]],3],0]
+[[[2,[6,9]],5],[[5,7],[5,[7,1]]]]
+[[[[3,1],[7,3]],[[1,0],[4,6]]],[[[4,9],[4,1]],[9,[2,0]]]]
+[[[5,0],[[9,4],6]],[1,[[0,4],[9,9]]]]
+[[[[9,8],3],[7,5]],[[[9,5],2],[9,9]]]
+[[8,[[8,0],[2,3]]],[[[3,8],[2,6]],[[1,0],0]]]
+[[[7,[7,1]],[[6,6],[2,9]]],[[5,[2,0]],[[3,9],[7,4]]]]
+[1,[4,[[9,7],[1,3]]]]
+[[0,3],[[[4,1],7],[[4,1],[3,0]]]]
+[[0,[[7,7],6]],[[4,9],2]]
+[[0,8],[4,[4,5]]]
+[[[8,[0,5]],[[1,3],[0,5]]],[[2,6],[1,5]]]
+[[[[7,6],8],[0,[2,7]]],8]
+[8,[[[5,4],8],[[2,1],[7,5]]]]
+[[[[7,3],[7,1]],0],[[[7,9],2],3]]
+[[8,5],[6,6]]
+[[[[5,2],8],7],[[[6,8],[1,0]],[[0,0],1]]]
+[[[[1,0],1],6],[9,8]]
+[[[[1,2],7],[1,[2,8]]],[[8,1],[[7,5],2]]]
+[[0,6],[[2,8],[9,0]]]
+[[[0,[7,7]],[2,[0,8]]],[[[7,4],4],[7,[4,0]]]]
+[[[2,[9,3]],[[3,7],3]],[[[9,7],[5,6]],8]]
+[[2,[[8,7],2]],[[8,[1,8]],[[7,2],1]]]
\ No newline at end of file
diff --git a/day5/day5 b/day5/day5
deleted file mode 100755
index c531a5d..0000000
Binary files a/day5/day5 and /dev/null differ
diff --git a/day9/input.txt.test b/day9/input.txt.test
deleted file mode 100644
index 6dee4a4..0000000
--- a/day9/input.txt.test
+++ /dev/null
@@ -1,5 +0,0 @@
-2199943210
-3987894921
-9856789892
-8767896789
-9899965678