implementTriePrefixTree.py

#! /usr/bin/env python3
# -*- coding: utf-8 -*-

# Source: https://leetcode.com/problems/implement-trie-prefix-tree/
# Author: Miao Zhang
# Date:   2021-01-26

class Trie:

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.root = {}
        self.end_of_word = '#'

    def insert(self, word: str) -> None:
        """
        Inserts a word into the trie.
        """
        node = self.root
        for c in word:
            node = node.setdefault(c, {})
        node[self.end_of_word] = self.end_of_word

    def search(self, word: str) -> bool:
        """
        Returns if the word is in the trie.
        """
        node = self.root
        for c in word:
            if c in node:
                node = node[c]
            else:
                return False
        if self.end_of_word in node:
            return True
        else:
            return False
        

    def startsWith(self, prefix: str) -> bool:
        """
        Returns if there is any word in the trie that starts with the given prefix.
        """
        node = self.root
        for c in prefix:
            if c in node:
                node = node[c]
            else:
                return False
        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)