day_9_olle.py

from typing import List
def read_file(filename: str) -> str:
    with open(filename) as f:
        return f.readline().strip()

def get_id_representation(file: str) -> List[str]:
    i = 0
    id_rep = []
    while i < len(file):
        if i % 2 == 0:
            id_rep += [str(i//2)]*int(file[i])
        else:
            id_rep += ['.']*int(file[i])
        i += 1
    return id_rep



def rearrange(id_rep: str) -> List[str]:
    i = 0
    j = len(id_rep) - 1
    rearranged_rep = []
    while i < j:
        while id_rep[i].isnumeric() and i < j:
            rearranged_rep += [id_rep[i]]
            i += 1
        while (id_rep[j] == '.') and i < j:
            j -= 1
        if i == j:
            break
        else:
            rearranged_rep += [id_rep[j]]
            i += 1
            j -= 1
    rearranged_rep += [id_rep[j]]
    print(len(id_rep))
    print(len(rearranged_rep))
    return rearranged_rep + ['.'] * (len(id_rep) - len(rearranged_rep))

def rearrange_whole(file: str) -> List[str]:
    file = list(file)
    ids = []
    i = 0
    for i in range(len(file)):
        if i % 2 == 0:
            ids += [str(i // 2)]
        else:
            ids += [str('.')]
    j = 1
    while j <= (len(file) - 1):
        if ids[-j] == '.':
            j += 1
            continue
        i = 0
        while (i < (len(file) - j) and
               (ids[i].isnumeric() or int(file[i]) < int(file[-j]))):
            i += 1
        if i == (len(file) - j):
            j += 1
            continue
        elif int(file[i]) == int(file[-j]):
            ids[i], ids[-j] = ids[-j], ids[i]
            file[i], file[-j] = file[-j], file[i]
            j += 1
        else:
            numel_to_keep = int(file[i]) - int(file[-j])
            file[i] = file[-j]
            file = file[:i+1] + [str(numel_to_keep)] + file[i+1:]
            ids[i], ids[-j] = ids[-j], ids[i]
            ids = ids[:i+1] + ['.'] + ids[i+1:]
            j += 2

    rearranged_file = []
    for i in range(len(file)):
        rearranged_file += [ids[i]]*int(file[i])
    return rearranged_file

            

def compute_checksum(arranged_file: List[str]) -> int:
    checksum = 0
    i = 0
    while arranged_file[i].isnumeric():
        checksum += int(arranged_file[i]) * i
        i += 1
    return checksum

def compute_checksum_whole(arranged_file: List[str]) -> int:
    checksum = 0
    i = 0
    for i in range(len(arranged_file)):
        if arranged_file[i].isnumeric():
            checksum += int(arranged_file[i]) * i
    return checksum


if __name__ == "__main__":
    file = read_file('input')
    id_rep = get_id_representation(file)
    print(compute_checksum(rearrange(id_rep)))
    print(compute_checksum_whole(rearrange_whole(file)))