Word Search in Trie in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a Trie node with an empty children map.

DSA Typescript

class TrieNode {
  children: Map<string, TrieNode> = new Map();
  isEndOfWord: boolean = false;
}

const node = new TrieNode();
node.children.[1]('a', new TrieNode());

Drag options to blanks, or click blank then click option'

Ainsert

Badd

Cpush

Dset

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'add' or 'push' which are not methods of Map.

Trying to assign directly without using a method.

The Map object uses the 'set' method to add key-value pairs. Here, 'a' is the key and a new TrieNode is the value.

2fill in blank

medium

Complete the code to check if a character exists in the children map of a Trie node.

DSA Typescript

function hasChild(node: TrieNode, char: string): boolean {
  return node.children.[1](char);
}

Drag options to blanks, or click blank then click option'

Ahas

Bcontains

Cincludes

Dexists

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'contains' or 'includes' which are not Map methods.

Trying to access children[char] directly without checking.

The Map object has a 'has' method to check if a key exists.

3fill in blank

hard

Fix the error in the insert method to correctly add characters to the Trie.

DSA Typescript

class Trie {
  root: TrieNode = new TrieNode();

  insert(word: string): void {
    let current = this.root;
    for (const char of word) {
      if (!current.children.[1](char)) {
        current.children.set(char, new TrieNode());
      }
      current = current.children.get(char)!;
    }
    current.isEndOfWord = true;
  }
}

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Aset

Bget

Chas

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'get' which returns a value, not a boolean.

Using 'set' which adds or updates a value, not checks existence.

We need to check if the children map has the character key before adding a new node. The 'has' method is used for this check.

4fill in blank

hard

Fill both blanks to complete the search method that returns true if the word exists in the Trie.

DSA Typescript

class Trie {
  root: TrieNode = new TrieNode();

  search(word: string): boolean {
    let current = this.root;
    for (const char of word) {
      if (!current.children.[1](char)) {
        return false;
      }
      current = current.children.[2](char)!;
    }
    return current.isEndOfWord;
  }
}

Drag options to blanks, or click blank then click option'

Ahas

Bget

Cset

Dcontains

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'set' instead of 'get' to retrieve a node.

Using 'contains' which is not a Map method.

To check if a character exists, use 'has'. To get the child node, use 'get'.

5fill in blank

hard

Fill all three blanks to complete the method that checks if any word in the Trie starts with the given prefix.

DSA Typescript

class Trie {
  root: TrieNode = new TrieNode();

  startsWith(prefix: string): boolean {
    let current = this.root;
    for (const char of prefix) {
      if (!current.children.[1](char)) {
        return false;
      }
      current = current.children.[2](char)!;
    }
    return [3];
  }
}

Drag options to blanks, or click blank then click option'

Ahas

Bget

Ctrue

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Returning false at the end instead of true.

Using 'set' instead of 'get' to retrieve nodes.

We check if each character exists with 'has', get the node with 'get', and if all characters are found, return true.