4 files changed, 2169 insertions, 0 deletions

diff --git a/day18/__init__.py b/day18/__init__.py
new file mode 100644
index 0000000..0500963
--- /dev/null
+++ b/day18/__init__.py
@@ -0,0 +1,75 @@
+# -*- coding: utf-8 -*-
+from abc import ABC
+from typing import Iterator, Set
+
+from aoc import BaseAssignment
+from aoc.datastructures import Coordinate3
+from aoc.mixins import BreathFirstSearchMixin
+
+
+class Assignment(BaseAssignment[int, Coordinate3], ABC):
+    def parse_item(self, item: str) -> Coordinate3:
+        x, y, z = item.split(",")
+        return Coordinate3(int(x), int(y), int(z))
+
+    @staticmethod
+    def open_sides(blocks: Set[Coordinate3]) -> int:
+        return len(
+            [
+                neighbour
+                for block in blocks
+                for neighbour in block.neighbours(True)
+                if neighbour not in blocks
+            ]
+        )
+
+
+class AssignmentOne(Assignment):
+    example_result = 64
+
+    def run(self, input: Iterator[Coordinate3]) -> int:
+        blocks = set(input)
+        return self.open_sides(blocks)
+
+
+class AssignmentTwo(Assignment, BreathFirstSearchMixin[Coordinate3]):
+    example_result = 58
+
+    def run(self, input: Iterator[Coordinate3]) -> int:
+        blocks = set(input)
+
+        lower_x = min([block.x for block in blocks]) - 1
+        higher_x = max([block.x for block in blocks]) + 1
+        lower_y = min([block.y for block in blocks]) - 1
+        higher_y = max([block.y for block in blocks]) + 1
+        lower_z = min([block.z for block in blocks]) - 1
+        higher_z = max([block.z for block in blocks]) + 1
+
+        all_coordinates = set(
+            Coordinate3(x, y, z)
+            for x in range(lower_x, higher_x + 1)
+            for y in range(lower_y, higher_y + 1)
+            for z in range(lower_z, higher_z + 1)
+        )
+
+        def nb(c):
+            for n in c.neighbours(True):
+                if n in all_coordinates and n not in blocks:
+                    yield n
+
+        outer_coordinates = {
+            coordinate
+            for coordinate in self.bfs(
+                Coordinate3(lower_x, lower_y, lower_z),
+                neighbours=nb,
+            )
+        }
+
+        return len(
+            [
+                neighbour
+                for block in blocks
+                for neighbour in block.neighbours(True)
+                if neighbour in outer_coordinates
+            ]
+        )
diff --git a/day18/example.txt b/day18/example.txt
new file mode 100644
index 0000000..73a7202
--- /dev/null
+++ b/day18/example.txt
@@ -0,0 +1,13 @@
+2,2,2
+1,2,2
+3,2,2
+2,1,2
+2,3,2
+2,2,1
+2,2,3
+2,2,4
+2,2,6
+1,2,5
+3,2,5
+2,1,5
+2,3,5
diff --git a/day18/input.txt b/day18/input.txt
new file mode 100644
index 0000000..acf8240
--- /dev/null
+++ b/day18/input.txt
@@ -0,0 +1,2057 @@
+4,15,12
+16,10,16
+15,15,10
+14,11,16
+5,7,15
+15,9,12
+8,5,3
+2,9,10
+13,16,9
+2,7,9
+6,5,5
+17,7,10
+6,13,15
+3,14,13
+4,14,13
+3,6,7
+5,16,7
+6,16,12
+16,13,6
+4,10,4
+3,5,8
+3,14,9
+14,9,1
+16,5,9
+16,12,15
+16,7,6
+4,4,9
+17,13,10
+13,4,14
+9,2,10
+5,4,12
+6,9,16
+10,2,13
+18,10,8
+6,4,4
+5,14,5
+7,9,18
+7,14,16
+7,4,15
+9,11,17
+12,10,16
+2,6,8
+5,13,4
+12,2,9
+14,4,16
+9,8,4
+4,10,3
+5,14,4
+13,16,13
+11,8,17
+16,8,15
+3,12,12
+13,13,16
+15,7,6
+13,16,7
+2,10,9
+3,11,5
+3,9,4
+11,15,14
+13,6,13
+4,12,4
+6,2,9
+5,13,9
+3,7,7
+14,8,16
+5,16,11
+7,16,13
+7,6,3
+8,4,4
+14,16,8
+18,7,9
+7,4,14
+14,11,4
+7,9,3
+12,8,1
+11,8,1
+6,15,7
+11,2,12
+1,7,9
+11,10,17
+2,11,6
+13,10,3
+16,13,12
+5,8,3
+8,5,2
+11,7,2
+7,18,12
+14,7,3
+5,10,16
+16,7,12
+9,7,1
+9,16,7
+6,9,17
+16,11,8
+14,12,4
+11,12,3
+7,17,12
+11,3,4
+5,5,14
+3,13,8
+7,17,8
+4,10,12
+16,15,8
+16,11,15
+3,3,9
+15,6,9
+12,4,7
+16,10,14
+16,9,5
+7,12,17
+17,13,9
+2,10,8
+5,3,10
+17,8,5
+12,17,13
+9,15,12
+8,6,16
+8,14,3
+7,2,12
+17,9,6
+7,11,17
+12,5,3
+15,16,9
+8,10,0
+14,9,17
+3,11,9
+15,7,15
+8,16,14
+3,12,15
+15,14,13
+2,9,12
+14,3,7
+9,4,5
+12,2,6
+12,16,11
+13,2,9
+7,15,14
+7,5,3
+17,7,7
+6,8,17
+10,1,9
+10,4,5
+4,17,10
+10,18,10
+8,7,16
+5,2,7
+7,11,2
+2,11,11
+10,3,15
+9,15,14
+9,4,4
+9,11,1
+8,12,16
+7,8,1
+10,3,5
+14,16,10
+4,7,16
+7,12,3
+16,13,14
+4,14,10
+13,2,7
+8,18,7
+10,15,3
+6,5,14
+18,11,12
+4,15,13
+15,5,14
+14,15,14