TRIE树 class Trie(object):   def init(self):  self.root = {}  self.end_of_word = "#" def insert(self, word):  node = self.root  for char in word:  node = node.setdefault(char, {})  node[self.end_of_word] = self.end_of_word def search(self, word):  node = self.root  for char in word:  if char not in node:  return False  node = node[char]  return self.end_of_word in node def startsWith(self, prefix):  node = self.root  for char in prefix:  if char not in node:  return False  node = node[char]  return True