Python数据结构与算法之字典树实现方法示例

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