Solve 2022 day 03

puzzles/solutions/2022/d03/p1.py

@@ -0,0 +1,60 @@
+import sys
+
+# Lowercase item types are numbered 1 through 26, uppercase item types are numbered 27 through 52.
+LOWERCASE_ITEM_TYPE_PRIORITY_ASCII_DIFFERENCE = ord("a") - 1
+UPPERCASE_ITEM_TYPE_PRIORITY_ASCII_DIFFERENCE = ord("A") - 27
+
+
+def get_rucksacks_compartments(
+    input_text: str,
+) -> list[tuple[set, set]]:
+    """
+    :param input_text: puzzle input
+    :return: list of (first compartment set, second compartment set) couples
+    """
+    return [
+        (
+            set(rucksack[: len(rucksack) // 2]),
+            set(rucksack[len(rucksack) // 2 :]),
+        )
+        for rucksack in input_text.splitlines()
+    ]
+
+
+def get_shared_item_type(first_compartment: set, second_compartment: set) -> str:
+    """
+    :param first_compartment: counter of item types in the first compartment
+    :param second_compartment: counter of item types in the second compartment
+    :return: shared item type between the two compartments
+    """
+    return (first_compartment & second_compartment).pop()
+
+
+def get_item_type_priority(item_type: str) -> int:
+    """
+    :param item_type: item type
+    :return: priority of the item type
+    """
+    difference = (
+        LOWERCASE_ITEM_TYPE_PRIORITY_ASCII_DIFFERENCE
+        if item_type.islower()
+        else UPPERCASE_ITEM_TYPE_PRIORITY_ASCII_DIFFERENCE
+    )
+    return ord(item_type) - difference
+
+
+def get_answer(input_text: str):
+    """Return the sum of the priorities of shared item types in all the rucksacks."""
+    rucksacks_compartments = get_rucksacks_compartments(input_text)
+    shared_items = "".join(
+        get_shared_item_type(first_compartment, second_compartment)
+        for first_compartment, second_compartment in rucksacks_compartments
+    )
+    return sum(map(get_item_type_priority, shared_items))
+
+
+if __name__ == "__main__":
+    try:
+        print(get_answer(sys.argv[1]))
+    except IndexError:
+        pass  # Don't crash if no input was passed through command line arguments.

puzzles/solutions/2022/d03/p2.py

@@ -0,0 +1,43 @@
+import functools
+import sys
+
+import p1
+
+
+GROUP_SIZE = 3
+
+
+def get_group_rucksacks(input_text: str) -> list[list[str]]:
+    """
+    :param input_text: puzzle input
+    :return: list of combined rucksacks in a group
+    """
+    rucksacks = input_text.splitlines()
+    groups = []
+    for rucksack_number in range(0, len(rucksacks), GROUP_SIZE):
+        group_rucksacks = rucksacks[rucksack_number : rucksack_number + GROUP_SIZE]
+        groups.append(group_rucksacks)
+    return groups
+
+
+def get_group_badge(group_rucksacks: list[str]) -> str:
+    """
+    :param group_rucksacks: list of rucksacks of the group
+    :return: group badge, which is the item type which is common between all rucksacks
+    """
+    group_rucksacks = map(set, group_rucksacks)
+    return tuple(functools.reduce(set.intersection, group_rucksacks))[0]
+
+
+def get_answer(input_text: str):
+    """Return the sum of the priorities of the item types that correspond to the badges of each three-Elf group."""
+    group_rucksacks = get_group_rucksacks(input_text)
+    badges = list(map(get_group_badge, group_rucksacks))
+    return sum((map(p1.get_item_type_priority, badges)))
+
+
+if __name__ == "__main__":
+    try:
+        print(get_answer(sys.argv[1]))
+    except IndexError:
+        pass  # Don't crash if no input was passed through command line arguments.