Advent of Code 2024, day 05

AdventOfCode2024.Day05.py

with open("./data/input05.txt") as inputFile:
    input = inputFile.read().splitlines()

orders = set()
updates = []

for line in input:
    if '|' in line:
        pages = line.split('|')
        orders.add((int(pages[0]), int(pages[1])))
    elif ',' in line:
        update = []
        pages = line.split(',')
        for page in pages:
            update.append(int(int(page)))
        updates.append(update)


def in_order(update):
    for order in orders:
        if order[0] in update and order[1] in update:
            n1 = update.index(order[0])
            n2 = update.index(order[1])
            if n1 > n2: return False
    return True

def get_middle_page(update):
    return update[int(len(update)/2)]

# Part 1

res = 0

for update in updates:
    if in_order(update):
        res += get_middle_page(update)

print(res)

# Part 2

def find_first_page(update):
    for page in update:
        is_first = True
        for order in orders:
            if order[0] in update and order[1] in update and page == order[1]:
                is_first = False
        if is_first: 
            return page

def reorder(before, after):
    if len(before) == 0: return after
    first_page = find_first_page(before)
    after.append(first_page)
    del before[before.index(first_page)]
    return reorder(before, after)

res = 0

for update in updates:
    if not(in_order(update)):
        res += get_middle_page(reorder(update, []))

print(res)