import aocd
import collections

def parse_rules(orders):
    """
    Return a dictionary mapping page numbers to lists of page numbers
    For any given key, each page of the value must come after it
    """
    rules = collections.defaultdict(list)

    for order in orders:
        k,v = order.split('|')
        rules[k].append(v)

    return rules

def update_is_incorrect(update, rules):
    for n, page in enumerate(update):
        for prev_n, prev_page in enumerate(update[:n]):
            if prev_page in rules[page]:
                return (n, prev_n)
    return False


def fix_update(update, rules):
    def insert_before(l, a, b):
        """
        Mutate l with the bth element moved to just before the ath
        """
        l.insert(a, l.pop(b))

    while (indices := update_is_incorrect(update, rules)):
        insert_before(update, *indices)

    return int(update[len(update)//2])


def solve(data):
    orders, updates = data.split('\n\n')
    updates = (u.split(',') for u in updates.split('\n'))
    rules = parse_rules(orders.split('\n'))

    incorrect = (u for u in updates if update_is_incorrect(u, rules))
    return sum(fix_update(u, rules) for u in incorrect)

if __name__ == '__main__':
    print('Warning: This is horrifically slow but I do not feel like spending time on a sorting problem', file=__import__('sys').stderr)
    puz = aocd.models.Puzzle(year=2024, day=5)

    # data = puz.examples[0].input_data
    data = puz.input_data

    solution = solve(data)

    print(solution)
    aocd.submit(solution, year=2024, day=5, part='b')