Solution #f0098ec5-21f6-4d91-b0b2-dfe210cb5ef5

def solve(input):
    try:
        data = input["data"] if isinstance(input, dict) and "data" in input else ""
        if not isinstance(data, str):
            data = str(data)
        n = len(data)
        if n == 0:
            return 0.0

        chars = sorted(set(data))
        idx = {c: i for i, c in enumerate(chars)}

        encoded = (
            ("" if len(chars) == 0 else "|".join(chars))
            + "#"
            + ",".join(map(lambda ch: str(idx[ch]), data))
        )

        parts = encoded.split("#", 1)
        if len(parts) != 2:
            return 999.0
        dict_part, seq_part = parts
        dec_chars = [] if dict_part == "" else dict_part.split("|")
        nums = [] if seq_part == "" else list(map(int, seq_part.split(",")))
        decoded = "".join(map(lambda k: dec_chars[k], nums))

        if decoded != data:
            return 999.0

        return float(len(encoded) / n)
    except:
        return 999.0