Advent of Code 2022 Day 25

def snafu_to_dec(num):
    result = 0
    for i in range(len(num)):
        char = num[-i-1]
        if char == '-':
            modifier = -1
        elif char == '=':
            modifier = -2
        else:
            modifier = int(char)
        result += (modifier * 5**i)
    return result

def dec_to_snafu(num):
    def get_leading_digits(n):
        k = 0
        while 5**(k+1) <= n:
            k += 1
        m = n // 5**k
        if m in (1, 2):
            return [(k, str(m))], n - m*5**k
        elif m == 3:
            return [(k+1, "1"), (k, "=")], n - m*5**k
        elif m == 4:
            return [(k+1, "1"), (k, "-")], n - m*5**k
    temp = num
    digits = []
    while temp != 0:
        new_digits, temp = get_leading_digits(temp)
        digits += new_digits
    print(digits)
    l = ['0' for _ in range(digits[0][0]+1)]
    for k, char in digits:
        l[-k-1] = char
    return ''.join(l)


total = 0
with open('input', 'r') as f:
    for line in f.readlines():
        total += snafu_to_dec(line.strip())

print(total)
dec_to_snafu(total)