Prefix Search Using Trie in DSA C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert a character into the Trie node's children.

DSA C++

node->children[[1]] = new TrieNode();

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

A'c' - 'a'

B'b' - 'a'

C'z' - 'a'

D'a' - 'a'

Attempts:

3 left

💡 Hint

Common Mistakes

Using the character directly without subtracting 'a'.

Using wrong character subtraction leading to wrong index.

The character 'c' minus 'a' gives the correct index 2 for the children array.

2fill in blank

medium

Complete the code to check if a prefix exists in the Trie.

DSA C++

if (node->children[[1]] == nullptr) return false;

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

A'm' - 'a'

B'x' - 'a'

C'p' - 'a'

D'z' - 'a'

Attempts:

3 left

💡 Hint

Common Mistakes

Checking wrong index for the character.

Not checking for nullptr before accessing children.

To check prefix starting with 'p', index is 'p' - 'a' = 15.

3fill in blank

hard

Fix the error in the code to mark the end of a word in the Trie.

DSA C++

node->[1] = true;

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

AisWord

BwordEnd

CendOfWord

DisEnd

Attempts:

3 left

💡 Hint

Common Mistakes

Using undefined or inconsistent variable names.

Forgetting to mark the end of word.

The standard name used is 'isEnd' to mark the end of a word.

4fill in blank

hard

Fill both blanks to complete the loop that traverses the Trie for a prefix.

DSA C++

for (int i = 0; i < [1]; i++) {
    int index = prefix[i] [2] 'a';
    if (node->children[index] == nullptr) return false;
    node = node->children[index];
}

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

Aprefix.size()

Bprefix.length()

C-

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '-' for index calculation.

Using wrong length function.

Use prefix.length() for length and subtract 'a' to get index.

5fill in blank

hard

Fill all three blanks to complete the function that inserts a word into the Trie.

DSA C++

void insert(string word) {
    TrieNode* node = root;
    for (int i = 0; i < [1]; i++) {
        int index = word[i] [2] 'a';
        if (node->children[index] == nullptr) {
            node->children[index] = new TrieNode();
        }
        node = node->children[index];
    }
    node->[3] = true;
}

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

Aword.size()

B-

CisEnd

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '-' for index calculation.

Not marking the end of the word.

Use word.size() for length, subtract 'a' for index, and mark isEnd true.