题目大意
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给定一个由许多词根组成的字典列表 dictionary，以及一个句子字符串 sentence。
要求：将句子中有词根的单词用词根替换掉。如果单词有很多词根，则用最短的词根替换掉他。最后输出替换之后的句子。
解题思路
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将所有的词根存入到前缀树（字典树）中。然后在树上查找每个单词的最短词根。
代码
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class Trie:
def __init__(self):
"""
Initialize your data structure here.
"""
self.children = dict()
self.isEnd = False
def insert(self, word: str) -> None:
"""
Inserts a word into the trie.
"""
cur = self
for ch in word:
if ch not in cur.children:
cur.children[ch] = Trie()
cur = cur.children[ch]
cur.isEnd = True
def search(self, word: str) -> str:
"""
Returns if the word is in the trie.
"""
cur = self
index = 0
for ch in word:
if ch not in cur.children:
return word
cur = cur.children[ch]
index += 1
if cur.isEnd:
break
return word[:index]
class Solution:
def replaceWords(self, dictionary: List[str], sentence: str) -> str:
trie_tree = Trie()
for word in dictionary:
trie_tree.insert(word)
words = sentence.split(" ")
size = len(words)
for i in range(size):
word = words[i]
words[i] = trie_tree.search(word)
return ' '.join(words)
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