improved day03

advent/days/day03/solution.py

@@ -6,33 +6,29 @@ day_num = 3
 
 
 def part1(lines: Iterator[str]) -> int:
-    return sum(Rucksack.find_double(line) for line in lines)
+    return sum(priority(find_double(line)) for line in lines)
 
 
 def part2(lines: Iterator[str]) -> int:
-    groups = [lines] * 3
-    zipped = zip(*groups, strict=True)
-    return sum(Rucksack.find_common(group) for group in zipped)
+    groups = zip(lines, lines, lines, strict=True)
+    return sum(priority(find_common_item(group)) for group in groups)
 
 
-class Rucksack:
-    @staticmethod
 def priority(char: str) -> int:
     """
     Returns the priority given to each item.
     It is assumed, that we are given a valid item
     """
-        num = ord(char)
-        if ord('a') <= num and num <= ord('z'):
-            return num - ord('a') + 1
-        if ord('A') <= num and num <= ord('Z'):
-            return num - ord('A') + 27
+    if 'a' <= char and char <= 'z':
+        return ord(char) - ord('a') + 1
+    if 'A' <= char and char <= 'Z':
+        return ord(char) - ord('A') + 27
     raise Exception(f"Unknown char: {char}")
 
-    @staticmethod
-    def find_double(rucksack: str) -> int:
+
+def find_double(rucksack: str) -> str:
     """
-        Finds the priority of the one item in both compartments.
+    Finds the one item in both compartments.
     It is assumed that there is only one such item
     """
     half = len(rucksack) // 2
@@ -40,16 +36,17 @@ class Rucksack:
     second = rucksack[half:]
     for item in first:
         if item in second:
-                return Rucksack.priority(item)
+            return item
     raise Exception("No double item")
 
-    @staticmethod
-    def find_common(group: tuple[str, ...]) -> int:
+
+def find_common_item(group: tuple[str, str, str]) -> str:
     """
     Finds the one item in all three rucksacks given.
     It is assumed that there is only one such item and group has exactly three rucksacks
     """
-        for item in group[0]:
-            if item in group[1] and item in group[2]:
-                return Rucksack.priority(item)
+    first, second, third = group
+    for item in first:
+        if item in second and item in third:
+            return item
     raise Exception("No common item found")