Solution #5ad7cf36-da24-42d7-b2a8-9aaa3c48bd6b

def solve(input):
    data = input.get("data", "")
    if not isinstance(data, str) or not data:
        return 999.0

    # Approach: LZ77 using a sliding window
    window_size = 255

    def compress(data):
        i = 0
        compressed = []
        while i < len(data):
            match_length = 0
            match_position = 0
            for j in range(max(0, i - window_size), i):
                length = 0
                while (i + length < len(data)) and (data[j + length] == data[i + length]):
                    length += 1
                    if length > match_length:
                        match_length = length
                        match_position = i - j
            if match_length > 0:
                compressed.append((match_position, match_length, data[i + match_length]))
                i += match_length + 1
            else:
                compressed.append((0, 0, data[i]))
                i += 1
        return compressed

    def decompress(compressed_data):
        decompressed = []
        for position, length, next_char in compressed_data:
            if position > 0:
                start = len(decompressed) - position
                for j in range(length):
                    decompressed.append(decompressed[start + j])
            decompressed.append(next_char)
        return ''.join(decompressed)

    compressed_data = compress(data)
    decompressed_data = decompress(compressed_data)

    if decompressed_data != data:
        return 999.0

    original_size = len(data) * 8  # assuming each char is 1 byte (8 bits)
    compressed_size = 0
    for pos, length, char in compressed_data:
        compressed_size += 8 + 8 + 8 

    if original_size == 0:
        return 999.0

    compression_ratio = compressed_size / original_size
    return 1.0 - compression_ratio