Trie.py

class TrieNode:
    
    
    def __init__(self):
        
        self.children = [None]*26
        self.isEndOfWord = False
    


class Trie:

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.root = self.getNode()
    def getNode(self):
        return TrieNode()
        
    def _charToIndex(self,ch):
        
        return ord(ch)-ord('a')
        
    def insert(self, word: str) -> None:
        """
        Inserts a word into the trie.
        """
        # check if present otherwise add
        
        pCrawl = self.root
        length = len(word)
        
        for level in range(length):
            
            index = self._charToIndex(word[level])
            
            if not pCrawl.children[index]:
                pCrawl.children[index] = self.getNode()
            pCrawl = pCrawl.children[index]
            
        pCrawl.isEndOfWord = True
        
    def search(self, word: str) -> bool:
        """
        Returns if the word is in the trie.
        """
        pCrawl = self.root
        length = len(word)
        
        for level in range(length):
            index = self._charToIndex(word[level])
            if not pCrawl.children[index]:
                return False
            pCrawl = pCrawl.children[index]
        
        return pCrawl!=None and pCrawl.isEndOfWord
        

    def startsWith(self, prefix: str) -> bool:
        """
        Returns if there is any word in the trie that starts with the given prefix.
        """
        pCrawl = self.root
        length = len(prefix)
        k = 0
        for level in range(length):
            
            index = self._charToIndex(prefix[level])
            
            if not pCrawl.children[index]:
                return False
            pCrawl = pCrawl.children[index]
            k+=1
        
        return k==length
        
        
        


# 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)