Solution #4f69822f-7da0-4d5c-ab24-6ee96e6730b8

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

    # Implementing LZ77 compression
    def lz77_compress(data, window_size=20):
        compressed_data = []
        i = 0
        while i < len(data):
            match_length = 0
            match_distance = 0
            start_search = max(0, i - window_size)
            
            for j in range(start_search, i):
                length = 0
                while (i + length < len(data) and
                       data[j + length] == data[i + length]):
                    length += 1
                    if i + length >= len(data):
                        break
                if length > match_length:
                    match_length = length
                    match_distance = i - j

            if match_length > 0:
                compressed_data.append((match_distance, match_length, data[i + match_length]))
                i += match_length + 1
            else:
                compressed_data.append((0, 0, data[i]))
                i += 1

        return compressed_data

    def lz77_decompress(compressed_data):
        decompressed_data = []
        for (distance, length, next_char) in compressed_data:
            if distance == 0:
                decompressed_data.append(next_char)
            else:
                start = len(decompressed_data) - distance
                for _ in range(length):
                    decompressed_data.append(decompressed_data[start])
                    start += 1
                decompressed_data.append(next_char)
        
        return ''.join(decompressed_data)

    compressed_data = lz77_compress(data)
    decompressed_data = lz77_decompress(compressed_data)

    if decompressed_data != data:
        return 999.0

    compressed_size = 0
    for (distance, length, next_char) in compressed_data:
        compressed_size += 3  # assume each tuple takes 3 bytes

    original_size = len(data)

    return 1.0 - (compressed_size / float(original_size))