aoc-2022/25.py

import math

lines = [line.strip() for line in open("25.input")]

def to_dec(num):
    total = 0
    for i, c in enumerate(reversed(num)):
        if c in ["0", "1", "2"]:
            total += (5 ** i) * int(c)
        elif c == "-":
            total -= (5 ** i)
        elif c == "=":
            total -= (5 ** i) * 2
    return total

def from_dec(num):
    if num == 1:
        return "1"

    rem = num
    exp = 0
    while num > to_dec("2" + "2" * exp):
        exp += 1


    result = []

    while exp >= 0:
        if rem == 0:
            result.append("0")
        elif rem >= to_dec("2" + "=" * exp):
            result.append("2")
            rem -= (5 ** exp) * 2
        elif rem >= to_dec("1" + "=" * exp):
            result.append("1")
            rem -= (5 ** exp) * 1
        elif rem <= to_dec("=" + "2" * exp):
            result.append("=")
            rem += (5 ** exp) * 2
        elif rem <= to_dec("-" + "2" * exp):
            result.append("-")
            rem += (5 ** exp)
        else:
            result.append("0")
        #print("res=", "".join(result), ", rem=", rem)

        exp -= 1

    return "".join(result)

result = sum(to_dec(line) for line in lines)

print(result, "=", from_dec(result))