from functools import reduce

with open("input/day10.txt") as f:
    size, input = 256, f.read().strip()


def part1(size, input):
    lengths = [int(i) for i in input.split(",")]

    ring = list(range(size))
    _, _, ring = hash_round(0, 0, ring, lengths)

    return ring[0] * ring[1]


def hash_round(pos, skip, ring, lengths):
    for length in lengths:
        assert length <= len(ring), "overlap undefined"

        tail = min(length, len(ring) - pos)
        head = max(length - tail, 0)

        a = pos + tail
        b = 0 + head

        prefix = ring[b:pos]
        inside = ring[pos:a] + ring[:b]
        suffix = ring[a:]

        assert length == len(inside)

        twisted = inside[::-1]

        ring = twisted[tail:] + prefix + twisted[:tail] + suffix
        pos = (pos + length + skip) % len(ring)
        skip += 1

    return pos, skip, ring


def part2(size, input):
    lengths = [ord(c) for c in input] + [17, 31, 73, 47, 23]

    pos, skip = 0, 0
    ring = list(range(size))
    for _ in range(64):
        pos, skip, ring = hash_round(pos, skip, ring, lengths)

    dense = [0] * 16
    for i in range(16):
        start = 16 * i
        block = ring[start : start + 16]
        dense[i] = reduce(int.__xor__, block)

    out = ""
    for d in dense:
        out += f"{d:02x}"
    return out


print(part1(size, input))
print(part2(size, input))