from typing import Generator
from collections.abc import Iterable

Bits = tuple[bool, ...]
Input = list[Bits]

def column(rows: Iterable[Bits], n: int) -> Generator[bool, None, None]:
    for row in rows:
        yield row[n]

def most_common(bits: Iterable[bool]) -> bool:
    count1: int = 0
    length: int = 0
    for b in bits:
        if b: count1 += 1
        length += 1
    return count1 >= length - count1

def bits_to_int(bits: Bits) -> int:
    return sum(b * 2 ** i for i, b in enumerate(reversed(bits)))

def part1(nums: Input) -> int:
    nbits: int = len(nums[0])
    gamma: Bits = tuple(most_common(column(inp, i)) for i in range(nbits))
    epsilon: Bits = tuple(not bit for bit in gamma)
    return bits_to_int(gamma) * bits_to_int(epsilon)

def part2_impl(nums: Input, complement: bool, bit: int = 0) -> Bits:
    if len(nums) == 1:
        return nums[0]
    target: bool = most_common(column(nums, bit))
    if complement:
        target = not target
    nums = list(filter(lambda n: n[bit] == target, nums))
    return part2_impl(nums, complement, bit + 1)

def part2(nums: Input) -> int:
    oxygen: Bits = part2_impl(nums, False)
    co2: Bits = part2_impl(nums, True)
    return bits_to_int(oxygen) * bits_to_int(co2)

inp: Input = [tuple(c == '1' for c in l.strip()) for l in open('3.in')]

print(part1(inp))
print(part2(inp))