Solution #1734c297-77a2-4f19-b5bd-105699bde61a

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

    # Implementing a simple dictionary-based compression
    def dictionary_compress(data):
        dictionary = {}
        compressed_data = []
        buffer = ""
        dict_size = 256

        for char in data:
            buffer_plus_char = buffer + char
            if buffer_plus_char in dictionary:
                buffer = buffer_plus_char
            else:
                if buffer:
                    compressed_data.append(dictionary[buffer])
                else:
                    compressed_data.append(ord(char))
                dictionary[buffer_plus_char] = dict_size
                dict_size += 1
                buffer = char

        if buffer:
            compressed_data.append(dictionary[buffer])

        return compressed_data

    def dictionary_decompress(compressed_data):
        dictionary = {i: chr(i) for i in range(256)}
        dict_size = 256
        result = []

        w = chr(compressed_data[0])
        result.append(w)

        for k in compressed_data[1:]:
            if k in dictionary:
                entry = dictionary[k]
            elif k == dict_size:
                entry = w + w[0]
            else:
                return None

            result.append(entry)

            dictionary[dict_size] = w + entry[0]
            dict_size += 1

            w = entry

        return ''.join(result)

    compressed_data = dictionary_compress(data)
    decompressed_data = dictionary_decompress(compressed_data)

    if decompressed_data != data:
        return 999.0

    compressed_size = len(compressed_data) * 2  # Assume each entry takes 2 bytes
    original_size = len(data)

    return 1.0 - (compressed_size / float(original_size))