Python按字符串长度排序函数开发求助：桶排序第三步实现困境

Hey there! Let's work through this bucket sort problem step by step—you're already halfway there, let's fix those tricky parts.

先修正你现有代码里的小问题 #

1. 计算最大长度L的逻辑错误 #

你当前的循环只会把最后一个单词的长度赋值给L，根本没找到真正的最大长度。正确的做法是先初始化L为0，再逐个比对更新：

# 修正后的Step 1
L = 0
for word in words:
    current_len = len(word)
    if current_len > L:
        L = current_len

2. 第三步：按长度分配单词到桶里 #

你不需要硬编码长度限制，只需要遍历每个单词，计算它的长度，然后放到对应索引的桶里就行。注意你注释里的规则：长度为1的单词放buckets[0]，长度为2的放buckets[1]，所以桶的索引是单词长度 - 1。代码如下：

# 修正后的Step 3
for word in words:
    word_len = len(word)
    buckets[word_len - 1].append(word)

完整修正后的代码 #

把这些修改整合后，完整的函数就可以正常工作了：

def empty_buckets(n):
    """Return a list with n empty lists. Assume n is a positive integer. """
    buckets = []
    for bucket in range(n):
        buckets.append([])
    return buckets

def bucket_sorted(words):
    """Return a new list with the same words, but by increasing length. Assume words is a non-empty list of non-empty strings. """
    # Step 1. Compute the maximum length L of all words.
    L = 0
    for word in words:
        current_len = len(word)
        if current_len > L:
            L = current_len
    # Step 2. Create a list of L empty lists (buckets).
    buckets = empty_buckets(L)
    # Step 3. Put each word in the bucket corresponding to its length
    for word in words:
        word_len = len(word)
        buckets[word_len - 1].append(word)
    # Step 4. Put all buckets together into a single list of words.
    newList = []
    for bucket in buckets:
        newList.extend(bucket)  # 用extend比+拼接列表更高效
    return newList

测试验证 #

用你给出的示例输入测试一下：

print(bucket_sorted(['my', 'name', 'is', 'John']))
# 输出结果：['my', 'is', 'name', 'John']

长度相同的单词会保持原输入的顺序，这是桶排序的稳定特性哦。

内容的提问来源于stack exchange，提问作者user11125584