## 题目描述：

LeetCode 648. Replace Words

In English, we have a concept called `root`, which can be followed by some other words to form another longer word - let's call this word `successor`. For example, the root `an`, followed by `other`, which can form another word `another`.

Now, given a dictionary consisting of many roots and a sentence. You need to replace all the `successor` in the sentence with the `root` forming it. If a `successor` has many `roots` can form it, replace it with the root with the shortest length.

You need to output the sentence after the replacement.

Example 1:

```Input: dict = ["cat", "bat", "rat"]
sentence = "the cattle was rattled by the battery"
Output: "the cat was rat by the bat"
```

Note:

1. The input will only have lower-case letters.
2. 1 <= dict words number <= 1000
3. 1 <= sentence words number <= 1000
4. 1 <= root length <= 100
5. 1 <= sentence words length <= 1000

## Python代码：

``````class TrieNode:
def __init__(self):
self.children = dict()
self.isWord = False

class Trie:

def __init__(self):
self.root = TrieNode()

def insert(self, word):
node = self.root
for letter in word:
child = node.children.get(letter)
if child is None:
child = TrieNode()
node.children[letter] = child
node = child
node.isWord = True

def search(self, word):
ans = ''
node = self.root
for letter in word:
node = node.children.get(letter)
if node is None: break
ans += letter
if node.isWord: return ans
return word

class Solution(object):
def replaceWords(self, dict, sentence):
"""
:type dict: List[str]
:type sentence: str
:rtype: str
"""
trie = Trie()
for word in dict: trie.insert(word)
ans = []
for word in sentence.split():
ans.append(trie.search(word))
return ' '.join(ans)
``````

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