diff --git a/res/2015/day18/test_input.txt b/res/2015/day18/test_input.txt
index e69de29..6ddce72 100644
--- a/res/2015/day18/test_input.txt
+++ b/res/2015/day18/test_input.txt
@@ -0,0 +1,6 @@
+.#.#.#
+...##.
+#....#
+..#...
+#.#..#
+####..
diff --git a/src/2015/Day18.cpp b/src/2015/Day18.cpp
index 264e396..a664f9b 100644
--- a/src/2015/Day18.cpp
+++ b/src/2015/Day18.cpp
@@ -2,30 +2,113 @@
 
 namespace y2015::day18
 {
-  REGISTER_DAY(2015, Day18, std::vector<int>, int);
+  REGISTER_DAY(2015, Day18, Array2D<char>, int);
 
-  REGISTER_TEST_EXAMPLE(2015, Day18, ExampleInput, 1, 0);
-  REGISTER_TEST(2015, Day18, Input, 1, 0);
-  REGISTER_TEST_EXAMPLE(2015, Day18, ExampleInput, 2, 0);
-  REGISTER_TEST(2015, Day18, Input, 2, 0);
+  REGISTER_TEST_EXAMPLE(2015, Day18, ExampleInput, 1, 4);
+  REGISTER_TEST(2015, Day18, Input, 1, 814);
+  REGISTER_TEST_EXAMPLE(2015, Day18, ExampleInput, 2, 7);
+  REGISTER_TEST(2015, Day18, Input, 2, 924);
 
   READ_INPUT(input)
   {
-    std::vector<int> vec;
-    std::string str;
-    while (getline(input, str))
-    {
-    }
-    return vec;
+    return Input::ReadArray2D(input);
   }
 
   OUTPUT1(input)
   {
-    return 0;
+    Array2D<char> array1 = input;
+    Array2D<char> array2 = input;
+    Array2D<char>* current = &array1;
+    Array2D<char>* other = &array2;
+    for (int i = 0; i < 100; i++)
+    {
+      current->Each(
+        [&other](const Array2D<char>& array, Index2D index)
+        {
+          int neighbors = array.GetNeighbors('#', index.x, index.y, true);
+          if (array[index] == '#')
+          {
+            if (neighbors < 2 || neighbors > 3)
+            {
+              (*other)[index] = '.';
+            }
+            else
+            {
+              (*other)[index] = '#';
+            }
+          }
+          else if (array[index] == '.')
+          {
+            if (neighbors == 3)
+            {
+              (*other)[index] = '#';
+            }
+            else
+            {
+              (*other)[index] = '.';
+            }
+          }
+        });
+      std::swap(current, other);
+    }
+
+    return current->Count('#');
   }
 
   OUTPUT2(input)
   {
-    return 0;
+    Array2D<char> array1 = input;
+    Array2D<char> array2 = input;
+    Array2D<char>* current = &array1;
+    Array2D<char>* other = &array2;
+    array1[Index2D{0, 0}] = '#';
+    array2[Index2D{0, 0}] = '#';
+    array1[Index2D{0, array1.height - 1}] = '#';
+    array2[Index2D{0, array1.height - 1}] = '#';
+    array1[Index2D{array1.width - 1, 0}] = '#';
+    array2[Index2D{array1.width - 1, 0}] = '#';
+    array1[Index2D{array1.width - 1, array1.height - 1}] = '#';
+    array2[Index2D{array1.width - 1, array1.height - 1}] = '#';
+    for (int i = 0; i < 100; i++)
+    {
+      current->Each(
+        [&other](const Array2D<char>& array, Index2D index)
+        {
+          if (index.x == 0 && index.y == 0)
+            return;
+          if (index.x == 0 && index.y == array.height - 1)
+            return;
+          if (index.x == array.width - 1 && index.y == 0)
+            return;
+          if (index.x == array.width - 1 && index.y == array.height - 1)
+            return;
+          int neighbors = array.GetNeighbors('#', index.x, index.y, true);
+          if (array[index] == '#')
+          {
+            if (neighbors < 2 || neighbors > 3)
+            {
+              (*other)[index] = '.';
+            }
+            else
+            {
+              (*other)[index] = '#';
+            }
+          }
+          else if (array[index] == '.')
+          {
+            if (neighbors == 3)
+            {
+              (*other)[index] = '#';
+            }
+            else
+            {
+              (*other)[index] = '.';
+            }
+          }
+        });
+      std::swap(current, other);
+    }
+
+    return current->Count('#');
   }
 }