Word Search in Trie in DSA Javascript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

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

DSA Javascript

function createNode() {
  return { children: [1] };
}

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

Anull

B[]

C{}

Dundefined

Attempts:

3 left

💡 Hint

Common Mistakes

Using an array [] instead of an object for children.

The children of a Trie node should be an empty object to hold child nodes by character keys.

2fill in blank

medium

Complete the code to check if a character exists in the current Trie node's children.

DSA Javascript

if (node.children.hasOwnProperty([1])) {
  // character exists
}

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

Achar

B'char'

Cnode

Dchildren

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string literal 'char' instead of the variable char.

We check if the children object has the key named by the variable char.

3fill in blank

hard

Fix the error in the search function to return true if the word is found in the Trie.

DSA Javascript

function search(word) {
  let node = root;
  for (let char of word) {
    if (!node.children.hasOwnProperty(char)) {
      return false;
    }
    node = node.children[[1]];
  }
  return node.isEnd === true;
}

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

Aword

Bchar

Cnode

Dchildren

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'word' or 'node' instead of 'char' as the key.

We must use the current character variable 'char' to move to the next node.

4fill in blank

hard

Fill both blanks to insert a word into the Trie correctly.

DSA Javascript

function insert(word) {
  let node = root;
  for (let char of word) {
    if (!node.children.hasOwnProperty([1])) {
      node.children[[2]] = createNode();
    }
    node = node.children[char];
  }
  node.isEnd = true;
}

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

Achar

Bword

Cnode

Dchildren

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variables like 'word' or 'node' instead of 'char'.

We check and add the child node using the current character 'char' in both blanks.

5fill in blank

hard

Fill all three blanks to create a function that searches for a prefix in the Trie.

DSA Javascript

function startsWith(prefix) {
  let node = root;
  for (let [1] of prefix) {
    if (!node.children.hasOwnProperty([2])) {
      return false;
    }
    node = node.children[[3]];
  }
  return true;
}

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

Achar

Bprefix

Dnode

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prefix' or 'node' instead of 'char' for keys.

The loop variable is 'char', and we use 'char' to check and move through children.