1 files changed, 55 insertions, 0 deletions
diff --git a/p45c.erl b/p45c.erl
new file mode 100755
index 0000000..57b680a
--- /dev/null
+++ b/p45c.erl
@@ -0,0 +1,55 @@
+-module(p45c).
+-export([solve/1]).
+
+triangles(F,M) -> F ! {1, [ (N * (N + 1)) div 2 || N <- lists:seq(1,M) ]}. 
+pentagons(F,M) -> F ! {2, [ (N * ((3 * N) - 1)) div 2 || N <- lists:seq(1,M) ]}. 
+hexagons(F,M) -> F ! {3, [ N * ((2 * N) + 1) || N <- lists:seq(1,M) ]}.
+
+max(M) -> M * ((2 * M) + 1).
+
+nums(M) ->
+	spawn(fun() -> triangles(self(),M) end),
+	spawn(fun() -> pentagons(self(),M) end),
+	spawn(fun() -> hexagons(self(),M) end),
+	{T, P, H} = receive
+		{1, X} ->
+			receive
+				{2, Y} ->
+					receive
+						{3, Z} -> {X, Y, Z}
+					end;
+				{3, Y} ->
+					receive
+						{2, Z} -> {X, Z, Y}
+					end
+			end;
+		{2, X} ->
+			receive
+				{1, Y} ->
+					receive
+						{3, Z} -> {Y, X, Z}
+					end;
+				{3, Y} ->
+					receive
+						{1, Z} -> {Z, X, Y}
+					end
+			end;
+		{3, X} ->
+			receive
+				{1, Y} ->
+					receive
+						{2, Z} -> {Y, Z, X}
+					end;
+				{2, Y} ->
+					receive
+						{1, Z} -> {Z, Y, X}
+					end
+			end
+	end,
+	[ E || E <- lists:seq(1,max(M)), lists:member(E,T), lists:member(E, P), lists:member(E,H) ].
+
+getnext([_]) -> "Keep trying.";
+getnext([40755,X|_]) -> X;
+getnext([_|T]) -> getnext(T).
+
+solve(M) -> getnext(nums(M)).