leetcode1032

 class StreamChecker:
     def __init__(self, words: 'List[str]'):
         self.maxLen = 0
         self.List = set(words)
         for w in self.List:
             self.maxLen = max(self.maxLen,len(w))
         self.STR = ''

     def query(self, letter: str) -> bool:

         if letter in self.List:
             return True
         else:
             self.STR += letter

             clen = len(self.STR)
             if clen > self.maxLen:
                 self.STR = self.STR[1:]

             for w in self.List:
                 lw = len(w)
                 ls = len(self.STR)
                 if ls >= lw and w == self.STR[ls-lw:]:
                     return True
             return False

此解决方案超时：

在上面的代码基础上，增加Trie数据结构，解决方案如下：

 class Node:
     def __init__(self):
         self.isWord = False
         self.next = [0]*26

 class StreamChecker:
     def __init__(self, words: 'List[str]'):
         self.maxLen = 0
         self.Trie = Node()
         dwords = set(words)
         for w in dwords:
             cur = self.Trie
             for i in range(len(w)-1,-1,-1):
                 c = w[i]
                 index = ord(c) - ord('a')
                 if not cur.next[index]:
                     cur.next[index] = Node()
                 cur = cur.next[index]
                 if i == 0:
                     cur.isWord = True
             self.maxLen = max(self.maxLen,len(w))
         self.STR = ''

     def query(self, letter: str) -> bool:
         self.STR += letter
         clen = len(self.STR)
         if clen > self.maxLen:
                 self.STR = self.STR[1:]

         cur = self.Trie
         for i in range(len(self.STR)-1,-1,-1):
             c = self.STR[i]
             index = ord(c) - ord('a')
             if not cur.next[index]:
                 return False
             else:
                 cur = cur.next[index]
                 if cur.isWord:
                     return True
         return False