在英語中，我們有一個叫做詞根(root)的概念，它可以跟著其他一些片語成另一個較長的單詞——我們稱這個詞為繼承詞(successor)。例如，詞根an，跟隨著單詞other(其他)，可以形成新的單詞another(另一個)。

現在，給定一個由許多詞根組成的詞典和一個句子。你需要將句子中的所有繼承詞用詞根替換掉。如果繼承詞有許多可以形成它的詞根，則用最短的詞根替換它。

你需要輸出替換之後的句子。

示例 1：

輸入：dictionary = ["cat","bat","rat"], sentence = "the cattle was rattled by the battery"
輸出："the cat was rat by the bat"
示例 2：

輸入：dictionary = ["a","b","c"], sentence = "aadsfasf absbs bbab cadsfafs"
輸出："a a b c"
示例 3：

輸入：dictionary = ["a", "aa", "aaa", "aaaa"], sentence = "a aa a aaaa aaa aaa aaa aaaaaa bbb baba ababa"
輸出："a a a a a a a a bbb baba a"
示例 4：

輸入：dictionary = ["catt","cat","bat","rat"], sentence = "the cattle was rattled by the battery"
輸出："the cat was rat by the bat"
示例 5：

輸入：dictionary = ["ac","ab"], sentence = "it is abnormal that this solution is accepted"
輸出："it is ab that this solution is ac"

提示：

1 <= dictionary.length<= 1000
1 <= dictionary[i].length <= 100
dictionary[i]僅由小寫字母組成。
1 <= sentence.length <= 10^6
sentence僅由小寫字母和空格組成。
sentence 中單詞的總量在範圍 [1, 1000] 內。
sentence 中每個單詞的長度在範圍 [1, 1000] 內。
sentence 中單詞之間由一個空格隔開。
sentence沒有前導或尾隨空格。

來源：力扣（LeetCode）
連結：https://leetcode-cn.com/problems/replace-words
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class Solution:
    def replaceWords(self, dictionary: List[str], sentence: str) -> str:
        sentence=list(sentence.split())
        res=[]
        for i in sentence:
            swap=[]
            for j in dictionary:
                if i.startswith(j):
                    swap.append(j)
            if not swap:
                res.append(i) 
            else:
                res.append(min(swap))
        return ' '.join(res)

class Solution(object):
    def replaceWords(self, roots, sentence):
        """
        :type dict: List[str]
        :type sentence: str
        :rtype: str
        """
        # Because the default constructor registered by defaultdict is only called when it is called for the first time, so you can define yourself here.
        # Trie is a function, calling it will return a defaultdict
        Trie = lambda:collections.defaultdict(Trie)
        # tri first calls Trie, returns a defalutdict, so tri is a defalutdict
        tri = Trie()
        END = True
        
        for root in roots:
            # dict.__getitem__ requires two parameters, the first is the dictionary object, the second is the key
            # At the beginning, the dictionary object is tri, the key is the first character c of root, and tri[c] will return a new dictionary.
            # New dictionary represents the child node of the node starting with the character c
            # By analogy, finally get a leaf node, it should be empty by default, we assign the value of the whole word to the place where the key is END
            reduce(dict.__getitem__, root, tri)[END] = root
        
        def replace(word):
            cur = tri
            for c in word:
                # Either this character is not in the successor node of the current node, or has encountered the shortest prefix
                if c not in cur or END in cur:break
                # Otherwise continue to traverse down
                cur = cur[c]
            # When returning, there are two possibilities. If cur does not have a corresponding prefix, then the word does not match the word, and the word is returned.
            # get operation does not affect the value of Trie
            return cur.get(END, word)