1 class StreamChecker: 2 def __init__(self, words: 'List[str]'): 3 self.maxLen = 0 4 self.List = set(words) 5 for w in self.List: 6 self.maxLen = max(self.maxLen,len(w)) 7 self.STR = '' 8 9 def query(self, letter: str) -> bool: 10 11 if letter in self.List: 12 return True 13 else: 14 self.STR += letter 15 16 clen = len(self.STR) 17 if clen > self.maxLen: 18 self.STR = self.STR[1:] 19 20 for w in self.List: 21 lw = len(w) 22 ls = len(self.STR) 23 if ls >= lw and w == self.STR[ls-lw:]: 24 return True 25 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：
1 class Node: 2 def __init__(self): 3 self.isWord = False 4 self.next = [0]*26 5 6 class StreamChecker: 7 def __init__(self, words: 'List[str]'): 8 self.maxLen = 0 9 self.Trie = Node() 10 dwords = set(words) 11 for w in dwords: 12 cur = self.Trie 13 for i in range(len(w)-1,-1,-1): 14 c = w[i] 15 index = ord(c) - ord('a') 16 if not cur.next[index]: 17 cur.next[index] = Node() 18 cur = cur.next[index] 19 if i == 0: 20 cur.isWord = True 21 self.maxLen = max(self.maxLen,len(w)) 22 self.STR = '' 23 24 def query(self, letter: str) -> bool: 25 self.STR += letter 26 clen = len(self.STR) 27 if clen > self.maxLen: 28 self.STR = self.STR[1:] 29 30 cur = self.Trie 31 for i in range(len(self.STR)-1,-1,-1): 32 c = self.STR[i] 33 index = ord(c) - ord('a') 34 if not cur.next[index]: 35 return False 36 else: 37 cur = cur.next[index] 38 if cur.isWord: 39 return True 40 return False