python数据结构与算法——字典树

 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

参考：http://blog.csdn.net/v_july_v/article/details/6897097