问题描述
Implement a trie with insert, search, and startsWith methods.
思路
用Dictionary做，用嵌套dictionary的方法实现
对于一个单词中的每个字母，存为key，而value则是新建的dictionary，里面存放以下一个字母作为key、新建的dictionary作为value，以此类推，并用特殊符号标记出单词结尾
例如，insert('cjh'), 就会得到{'c': {'j': {'h': {'$': '$'}}}}
def __init__(self):
"""
Initialize your data structure here.
"""
self.root = {}
def insert(self, word):
"""
Inserts a word into the trie.
:type word: str
:rtype: void
"""
curDict = self.root
for x in word:
if x not in curDict:
curDict[x] = {}
curDict = curDict[x]
curDict['$'] = '$'
# print(self.root)
def search(self, word):
"""
Returns if the word is in the trie.
:type word: str
:rtype: bool
"""
curDict = self.root
for i in word:
if i not in curDict:
return False
curDict = curDict.get(i)
if '$' in curDict:
return True
return False
def startsWith(self, prefix):
"""
Returns if there is any word in the trie that starts with the given prefix.
:type prefix: str
:rtype: bool
"""
curDict = self.root
for i in prefix:
if i not in curDict:
return False
curDict =curDict.get(i)
return True
参考
https://leetcode.com/problems/implement-trie-prefix-tree/discuss/130893/Python-184ms-beats-100
