Longest Word in Dictionary Using Trie in DSA Go - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new Trie node.

DSA Go

type TrieNode struct {
    children [26]*TrieNode
    isEnd bool
}

func NewTrieNode() *TrieNode {
    return &TrieNode{
        children: [26]*TrieNode{},
        isEnd: [1],
    }
}

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

Atrue

Bnil

Cfalse

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Setting isEnd to true initially, which incorrectly marks the node as end of a word.

When creating a new Trie node, the isEnd flag should be false initially because no word ends at this node yet.

2fill in blank

medium

Complete the code to insert a word into the Trie.

DSA Go

func (t *TrieNode) Insert(word string) {
    node := t
    for _, ch := range word {
        index := ch - 'a'
        if node.children[index] == nil {
            node.children[index] = NewTrieNode()
        }
        node = node.children[[1]]
    }
    node.isEnd = true
}

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

Ach

Bindex

Cnode

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using the character directly instead of the index to access children.

Using the word or node variable incorrectly.

We use the calculated index to move to the correct child node for the current character.

3fill in blank

hard

Fix the error in the DFS function to find the longest word.

DSA Go

func dfs(node *TrieNode, path string, result *string) {
    if !node.isEnd && len(path) > 0 {
        return
    }
    if len(path) > len(*result) || (len(path) == len(*result) && path < *result) {
        *result = path
    }
    for i := 0; i < 26; i++ {
        if node.children[i] != nil {
            dfs(node.children[i], path+string('a'+[1]), result)
        }
    }
}

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

Aresult

Bnode

Cpath

Di

Attempts:

3 left

💡 Hint

Common Mistakes

Using node or path instead of the loop index i to calculate the character.

Appending wrong characters causing incorrect word formation.

We add the character corresponding to index i to the path during DFS traversal.

4fill in blank

hard

Fill both blanks to complete the function that finds the longest word in the dictionary using Trie.

DSA Go

func longestWord(words []string) string {
    root := NewTrieNode()
    for _, word := range words {
        root.[1](word)
    }
    result := ""
    dfs(root, "", &result)
    return [2]
}

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

AInsert

BSearch

Cresult

Dwords

Attempts:

3 left

💡 Hint

Common Mistakes

Using Search instead of Insert to add words.

Returning the wrong variable.

We insert each word into the Trie, then return the result found by DFS.

5fill in blank

hard

Fill all three blanks to complete the DFS helper function that builds the longest word.

DSA Go

func dfs(node *TrieNode, path string, result *string) {
    if !node.isEnd && len(path) > 0 {
        return
    }
    if len(path) > len(*result) || (len(path) == len(*result) && path < *result) {
        *result = path
    }
    for [1] := 0; [2] < 26; [3]++ {
        if node.children[[1]] != nil {
            dfs(node.children[[1]], path+string('a'+[1]), result)
        }
    }
}

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

Ai

Bj

Ck

Dindex

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names in loop parts causing syntax errors.

The loop variable i is used consistently for initialization, condition, and increment.