day 2 solution

lib/advent_of_code/day_02.ex

@@ -1,7 +1,9 @@
 defmodule AdventOfCode.Day02 do
-  def part1(_args) do
+  def part1(input) do
+    Advent.Code2_1.sum(My.Utils.split_file(input))
   end
 
-  def part2(_args) do
+  def part2(input) do
+    Advent.Code2_2.sum(My.Utils.split_file(input))
   end
 end

lib/code/day2_1.ex

@@ -0,0 +1,65 @@
+defmodule Advent.Code2_1 do
+  def conditions(),
+    do: %{
+      red: 12,
+      green: 13,
+      blue: 14
+    }
+
+  @spec is_possible(String.t(), String.t(), any()) :: integer()
+  def is_possible(game, color, color_symbol) do
+    [_, data] = String.split(game, ":")
+    draws = String.split(data, ";")
+
+    possible =
+      draws
+      |> Enum.map(fn draw -> Regex.run(~r/\d+ #{color}/, draw) end)
+      |> Enum.filter(fn el -> el != nil end)
+      |> Enum.flat_map(fn el -> el end)
+      |> Enum.map(fn el ->
+        case String.split(el, " ", parts: 2) do
+          [num, _] ->
+            {_, maximum} = Map.fetch(conditions(), color_symbol)
+            {real_num, _} = Integer.parse(num)
+
+            if(maximum >= real_num) do
+              true
+            else
+              false
+            end
+
+          [] ->
+            false
+        end
+      end)
+      |> Enum.filter(fn el -> el != true end)
+      |> length() == 0
+
+    if(possible) do
+      1
+    else
+      0
+    end
+  end
+
+  def extract_id(game) do
+    [game_id, _] = String.split(game, ":")
+    [_, id] = String.split(game_id, " ")
+    {result, _} = Integer.parse(id)
+    result
+  end
+
+  def sum(str_list) do
+    Enum.reduce(str_list, 0, fn el, acc ->
+      acc +
+        case is_possible(el, "red", :red) + is_possible(el, "green", :green) +
+               is_possible(el, "blue", :blue) do
+          3 ->
+            extract_id(el)
+
+          _ ->
+            0
+        end
+    end)
+  end
+end

lib/code/day2_2.ex

@@ -0,0 +1,32 @@
+defmodule Advent.Code2_2 do
+  def get_max_balls(game, color) do
+    [_, data] = String.split(game, ":")
+    draws = String.split(data, ";")
+
+    draws
+    |> Enum.map(fn draw -> Regex.run(~r/\d+ #{color}/, draw) end)
+    |> Enum.filter(fn el -> el != nil end)
+    |> Enum.flat_map(fn el -> el end)
+    |> Enum.map(fn el ->
+      [num, _] = String.split(el)
+      {result, _} = Integer.parse(num, 10)
+      result
+    end)
+    |> Enum.max()
+  end
+
+  def extract_id(game) do
+    [game_id] = String.split(game, ":")
+    [_, id] = String.split(game_id, " ")
+    {result, _} = Integer.parse(id)
+    result
+  end
+
+  def sum(str_list) do
+    Enum.reduce(str_list, 0, fn el, acc ->
+      acc +
+        get_max_balls(el, "red") * get_max_balls(el, "green") *
+          get_max_balls(el, "blue")
+    end)
+  end
+end

test/advent_of_code/day_02_test.exs

@@ -3,19 +3,35 @@ defmodule AdventOfCode.Day02Test do
 
   import AdventOfCode.Day02
 
-  @tag :skip
+  defp test_case1,
+    do: """
+    Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+    Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+    Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+    Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+    Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green
+    """
+
   test "part1" do
-    input = nil
+    input = test_case1()
     result = part1(input)
 
-    assert result
+    assert result == 8
   end
 
-  @tag :skip
+  defp test_case2,
+    do: """
+      Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+      Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+      Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+      Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+      Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 gree
+    """
+
   test "part2" do
-    input = nil
+    input = test_case2()
     result = part2(input)
 
-    assert result
+    assert result == 2286
   end
 end