class TrieTree():

     def __init__(self):

         self.root = {}

     def addNode(self,str):

         # 树中每个结点(除根节点)，包含到该结点的单词数，以及该结点后面出现字母的键

         nowdict = self.root

         for i in range(len(str)):

             if str[i] not in nowdict:    # 发现新的组合方式

                 nowdict[str[i]] = {'count':0,'prefix':str[:i+1]}

             nowdict = nowdict[str[i]]    # 转移到下一个结点

         nowdict['count'] += 1

     def countWord(self,str):

         # 返回输入单词在树中出现的次数

         nowdict = self.root

         for s in str:

             if s not in nowdict:

                 return 0

             nowdict = nowdict[s]    # 匹配当前结点,转下一个结点

         # 到了这一步证明单词存在

         return nowdict['count']

 if __name__=="__main__":

     pass

     Text = ['b','abc','abd','bcd','abcd','efg','hii','bcd']

     t = TrieTree()

     for str in Text:

         t.addNode(str)

     print t.countWord('bcd')

 >>> 2