如何在给出组合时计算指数(词典顺序)

def calculate_combinations(words, length):
    if length == 0:
        return []
    if length == 1:
        return words
    result = []
    for i in range(len(words)):
        current_word = words[i]
        remaining_words = words[i+1:]
        for combination in calculate_combinations(remaining_words, length-1):
            result.append([current_word] + combination)
    return result

dictionary = ['apple', 'banana', 'cherry']
combinations = calculate_combinations(dictionary, 3)
sorted_combinations = sorted(combinations, key=lambda x: ''.join(x))

def calculate_exponent(combinations):
    result = []
    for combination in combinations:
        exponent = sum(len(word) for word in combination)
        result.append(exponent)
    return result

exponents = calculate_exponent(sorted_combinations)