day3-part2-working.py

import sys

total = 0

# Read the input file from the command line arguments
with open(sys.argv[1], "r") as f:
    # Initialize a list to store the lines in groups of three
    group = []

    # Read each line of the input file
    for line in f:
        # Add the line to the current group
        group.append(line)

        # If the group has three lines, process it
        if len(group) == 3:
            # Initialize a set to keep track of which characters have already been added to the total
            added = set()

            # Iterate through each character in the first line of the group
            for ch in group[0]:
                # If the character also appears in the other lines,
                # and has not already been added to the total,
                # add its priority to the running total
                if all(ch in line for line in group[1:]) and ch not in added:
                    # Lowercase item types have priorities 1 through 26
                    if ch.islower():
                        total += ord(ch) - ord("a") + 1
                    # Uppercase item types have priorities 27 through 52
                    elif ch.isupper():
                        total += ord(ch) - ord("A") + 27
                    # Mark the character as added
                    added.add(ch)

            # Clear the group
            group = []

# Print the sum of the priorities of the item types that correspond to the badges
# of each group
print(total)