LC208 Implement Trie

class TrieNode:
    def __init__(self):
        self.children = {}#self.children = collections.defaultdict(TrieNode)  
        self.isEnd = False 


class Trie:
    def __init__(self):
        self.root = TrieNode()
    def insert(self, word: str) -> None:
        """ tc O(W) sc O(W)  W: length of word
        """
        cur = self.root 
        for c in word:
            if c not in cur.children:
                cur.children[c] = TrieNode()
            cur = cur.children[c]
        cur.isEnd = True 
        
    
    def search(self, word: str) -> bool:
        """ tc O(W) sc O(1)  W: length of word
        """
        cur = self.root
        for c in word:
            if c not in cur.children:
                return False
            cur = cur.children[c]
        return cur.isEnd 

    def search(self, word: str) -> bool:
        """tc O(W) sc O(1)  W: length of word
        """
        cur = self.root
        for c in word:
            if c not in cur.children:
                return False
            cur = cur.children[c]
        return cur.isEnd 
        

    def startsWith(self, prefix: str) -> bool:
        """ tc O(P) sc O(1) P: length of prefix 
        """
        cur = self.root
        for c in prefix:
            if c not in cur.children:
                return False 
            cur = cur.children[c]
        return True 
        


# Your Trie object will be instantiated and called as such:
# obj = Trie()
# obj.insert(word)
# param_2 = obj.search(word)
# param_3 = obj.startsWith(prefix)