RucksackReorganization.py

#!/usr/bin/python3
"""Template.py
    Author: Bissallah Ekele - bAe
    Date: 06/12/2022
    Description: Reorganizing one item in each Rucksack.
"""

# Slicing being memory hungry, an itch

def get_common_item(rucksack):
    """Find common character in both halves

        Keyword argument:
        rucksack -- string of items in a rucksack

        Return:
        string symbol of common item
    """
    bound = len(rucksack)/2

    for item in rucksack[0:bound]:
        if item in set(rucksack[bound:]):
            return item

def get_priority(item):
    """Derive item priority

        Keyword argument:
        item -- common item string

        Return:
        int priority of item
    """
    if item.isupper():        
        return ord(item) - (ord("A") - 27)

    return ord(item) - (ord("a") - 1)
    

def get_part_1(input_list):
    """Sum of priorities of common items

        Keyword argument:
        input_list -- list of rucksack

        Return:
        Priority sum int
    """
    total = 0

    for rucksack in input_list:
        common_item = get_common_item(rucksack)
        total += get_priority(common_item)
    
    return total

# Pseudocode:
# ensure group of threes from input-list
# find badge - 1 common item between 3 elves
# derive priority sum

def get_badge(group):
    """Get the common item between 3 elf's rucksack

        Keyword argument:
        group -- list of 3 elf rucksacks

        Return:
        Common item string
    """
    for item in group[0]:
        if (
            (item in set(group[1]))
            and (item in set(group[2]))
        ):
            return item

def get_part_2(input_list):
    """Find badge to update authenticity sticker

        Keyword argument:
        input_list -- list of rucksack

        Return:
        Priority sum int

        *Throws:
        Invalid input-list
    """
    total = 0

    if len(input_list) % 3 != 0:
        print("Invalid input list provided - Must be group of 3s.")

    for position in range(0,len(input_list),3):
        badge = get_badge(input_list[position:position+3])
        total += get_priority(badge)
    
    return total
    
def main():
    test_input = "test-input"
    puzzle_input = "puzzle-input"

    file_name = puzzle_input #test_input

    with open(file_name) as f:
        input_list = f.read().splitlines()

    print("Day_1 Part_1: " 
        + str(get_part_1(input_list)) 
        + "\nPart_2: "
        + str(get_part_2(input_list)))

if __name__ == "__main__":
    main()