1 files changed, 60 insertions, 0 deletions

diff --git a/day3/__init__.py b/day3/__init__.py
new file mode 100644
index 0000000..a9e1506
--- /dev/null
+++ b/day3/__init__.py
@@ -0,0 +1,60 @@
+# -*- coding: utf-8 -*-
+from abc import ABC
+from typing import Iterator, Any, List, Tuple
+
+from aoc import BaseAssignment
+
+
+class Assignment(BaseAssignment, ABC):
+    def calculate_priority(self, item: str) -> int:
+        ascii_nr = ord(item)
+
+        if ascii_nr >= 97:
+            return ascii_nr - 96
+
+        return ascii_nr - 38
+
+
+class AssignmentOne(Assignment):
+    example_result = 157
+
+    def split_rucksack(self, rucksack: str) -> Tuple[str, str]:
+        half = len(rucksack) // 2
+        return rucksack[:half], rucksack[half:]
+
+    def find_common(self, rucksack: str) -> str:
+        compartment_one, compartment_two = self.split_rucksack(rucksack)
+        overlapping = set(compartment_one).intersection(compartment_two)
+
+        return overlapping.pop()
+
+    def run(self, input: Iterator) -> Any:
+        return sum(
+            [
+                self.calculate_priority(self.find_common(rucksack=rucksack))
+                for rucksack in input
+            ]
+        )
+
+
+class AssignmentTwo(Assignment):
+    example_result = 70
+
+    def run(self, input: Iterator) -> Any:
+        prioritisation = []
+
+        while True:
+            try:
+                rucksack_1 = set(next(input))
+                rucksack_2 = set(next(input))
+                rucksack_3 = set(next(input))
+
+                prioritisation.append(
+                    self.calculate_priority(
+                        rucksack_1.intersection(rucksack_2, rucksack_3).pop()
+                    )
+                )
+            except StopIteration:
+                break
+
+        return sum(prioritisation)