Question

want to create a prefix tree in python (3)

2 ADTs Node and PrefixTree

Looking to create Node class with :

-__contains__(letter) - returns true if the Node has a child corresponding to the letter

-__getitem__(let) - returns the child node corresponding to the letter

-add_sub(tok, value) - adds a child to the node under the given token, also handle the case if a child already exists (it should only change the value of the child)

-remove_sub(let) - removes the child node corresponding to a given letter

this is the ADT:

class Node:
def __init__(self, value = None):
self.subs = {}
self._value = value
self.last = True

Answer 1

"endofWord ""S"" def generateTrieFromWordsArray (words): for word in words: currentDict = root for letter in word: currentDict = currentDict . setdefault (letter, { }) currentDict [endofword] = endofword return root def iswordPresentInTrie(trie, word): currentDict = trie for letter in word: if letter in currentDict = currentDict-currentDict [letter] else: return False if endofword in currentDict: return True else: return False "