solve 2015 day 15

2015/README.md

@@ -16,7 +16,7 @@
 | :--: | :--: | :-:  | :-: | :-:  | :-:  | :-:  |
 |      |      | [1]  | [2] | [3]  | [4]  | [5]  |
 |  [6] | [7]  | [8]  | [9] | [10] | [11] | [12] |
-| [13] | [14] | 15  | 16  | 17   | 18   | 19   |
+| [13] | [14] | [15] | 16  | 17   | 18   | 19   |
 |  20  | 21   | 22   | 23  | 24   | 25   |      |
 
 [1]: ./lib/2015/1.ex
@@ -33,3 +33,4 @@
 [12]: ./lib/2015/12.ex
 [13]: ./lib/2015/13.ex
 [14]: ./lib/2015/14.ex
+[15]: ./lib/2015/15.ex

2015/lib/2015/15.ex

@@ -15,12 +15,52 @@ aoc 2015, 15 do
     {name, [capacity, durability, flavor, texture], calories}
   end
 
+  def compile_ingredient({_label, coefficients, _cal}) do
+    fn v -> coefficients |> Enum.map(&(&1 * v)) end
+  end
+
   def p1 do
+    ingredients =
       input_stream()
-    |> Stream.map(&parse_ingredient/1)
-    |> Enum.to_list()
+      |> Enum.map(&parse_ingredient/1)
+      |> Enum.map(&compile_ingredient/1)
+
+    for i <- 1..100,
+        j <- 1..(100 - i),
+        k <- 1..(100 - (i + j)),
+        l <- 1..(100 - (i + j + k)),
+        i + j + k + l == 100 do
+      Enum.zip(ingredients, [i, j, k, l])
+      |> Enum.map(fn {fun, arg} -> apply(fun, [arg]) end)
+      |> List.zip()
+      |> Enum.map(fn t -> max(0, Tuple.sum(t)) end)
+      |> Enum.product()
+    end
+    |> Enum.sort(:desc)
+    |> hd()
   end
 
   def p2 do
+    ingredients =
+      input_stream()
+      |> Enum.map(&parse_ingredient/1)
+
+    [m, n, o, p] = ingredients |> Enum.map(&elem(&1, 2))
+
+    compiled_ingredients = Enum.map(ingredients, &compile_ingredient/1)
+
+    for i <- 1..100,
+        j <- 1..(100 - i),
+        k <- 1..(100 - (i + j)),
+        l <- 1..(100 - (i + j + k)),
+        i + j + k + l == 100 and i * m + j * n + k * o + l * p == 500 do
+      Enum.zip(compiled_ingredients, [i, j, k, l])
+      |> Enum.map(fn {fun, arg} -> apply(fun, [arg]) end)
+      |> List.zip()
+      |> Enum.map(fn t -> max(0, Tuple.sum(t)) end)
+      |> Enum.product()
+    end
+    |> Enum.sort(:desc)
+    |> hd()
   end
 end