aoc-2022/17.py

lines = [line.split() for line in open("17.input")]

jets = lines[0][0]

blocks = [
        [(0, 0), (1, 0), (2, 0), (3, 0)],
        [(1, 0), (0, 1), (1, 1), (2, 1), (1, 2)],
        [(2, 0), (2, 1), (0, 2), (1, 2), (2, 2)],
        [(0, 0), (0, 1), (0, 2), (0, 3)],
        [(0, 0), (0, 1), (1, 0), (1, 1)],
        ]

def show(occupied):
    stack_height = min([pos[1] for pos in occupied] + [0])

    for y in range(stack_height, 0):
        print("|", end='')
        for x in range(7):
            if (x, y) in occupied:
                print("#", end='')
            else:
                print(".", end='')
        print("|")
    print("-" * 9)


def add(a, b):
    return (a[0] + b[0], a[1] + b[1])

def run(target_blocks):
    occupied = set([(x, 0) for x in range(9)])
    jet_idx = 0

    combos = set()
    target = None
    found = []

    block_count = 0

    time_skip = False

    while block_count < target_blocks:
        block_idx = block_count % len(blocks)

        stack_height = min([pos[1] for pos in occupied] + [0])

        if not found:
            if (jet_idx, block_idx) in combos:
                # Set our target for time skip
                target = (jet_idx, block_idx)
                found.append((block_count, stack_height))
                print("Found repetition after", block_count, "blocks")
            else:
                combos.add((jet_idx, block_idx))
        elif not time_skip:
            if (jet_idx, block_idx) == target:
                print("Found again after", block_count)
                found.append((block_count, stack_height))
                if len(found) == 2:
                    chunk_blocks = found[-1][0] - found[-2][0]
                    chunk_height = -(found[-1][1] - found[-2][1])
                    extra_chunks = (target_blocks - block_count) // chunk_blocks
                    extra_blocks = extra_chunks * chunk_blocks
                    block_count += extra_blocks
                    extra_height = extra_chunks * chunk_height
                    print(f"Performing time-skip (+{extra_blocks} blocks, +{extra_height} height).")
                    occupied = {add(pos, (0, -extra_height)) for pos in occupied}
                    time_skip = True
                    continue


        block = blocks[block_idx]

        b_height = max(pos[1] for pos in block)

        start_pos = (2, stack_height - b_height - 4)

        block = [add(pos, start_pos) for pos in block]

        #show(occupied.union(block))

        while True:
            # Jetting
            max_x = max(pos[0] for pos in block)
            min_x = min(pos[0] for pos in block)

            jet = jets[jet_idx]
            jet_idx += 1
            jet_idx = jet_idx % len(jets)

            if min_x > 0 and jet == '<':
                next_block = {add(pos, (-1, 0)) for pos in block}
            elif max_x < 6 and jet == '>':
                next_block = {add(pos, (1, 0)) for pos in block}

            if not next_block.intersection(occupied):
                block = next_block

            # Falling
            next_block = {add(pos, (0, 1)) for pos in block}

            if next_block.intersection(occupied):
                occupied = occupied.union(block)
                break
            else:
                block = next_block

        block_count += 1

    stack_height = min([pos[1] for pos in occupied] + [0])
    return -stack_height


print("Part 1:", run(2022))
print("Part 2:", run(1000000000000))