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Prefix Tree

Certification: Intermediate Level Accuracy: 0% Submissions: 0 Points: 10

Write a JavaScript program to implement a Trie (Prefix Tree) data structure. A trie is a tree-like data structure that stores a dynamic set of strings, where the keys are usually strings. Your Trie should support inserting strings, searching for complete words, and checking if any word starts with a given prefix.

Example 1
    
      
  • Input: Operations = ["insert", "search", "search", "startsWith", "insert", "search"], Values = ["apple", "apple", "app", "app", "app", "app"]
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  • Output: [null, true, false, true, null, true]
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  • Explanation: 
    • Insert "apple" into the trie. 
    • Search for "apple" - returns true as it exists. 
    • Search for "app" - returns false as complete word doesn't exist. 
    • Check if any word starts with "app" - returns true. Insert "app" into the trie. 
    • Search for "app" - now returns true as complete word exists.
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Example 2
    
      
  • Input: Operations = ["insert", "insert", "search", "search", "startsWith"], Values = ["hello", "help", "hell", "hello", "hel"]
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  • Output: [null, null, false, true, true]
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  • Explanation: 
    • Insert "hello" into the trie. 
    • Insert "help" into the trie. 
    • Search for "hell" - returns false as complete word doesn't exist. 
    • Search for "hello" - returns true as it exists. 
    • Check if any word starts with "hel" - returns true.
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Constraints
    
      
  • 1 ≤ word.length, prefix.length ≤ 2000
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  • word and prefix consist only of lowercase English letters
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  • At most 3 * 10^4 calls in total will be made to insert, search, and startsWith
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  • Time Complexity: O(m) for each operation where m is the length of the word
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  • Space Complexity: O(ALPHABET_SIZE * N * M) where N is number of words and M is average length
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Trie MapGoldman SachsArctwist
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Hint
Solution

Solution Hints

    
      
  • Create a TrieNode class with an array to store children and a boolean flag for end of word
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  • Use an object or Map to represent children nodes for each character
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  • For insertion, traverse the trie creating new nodes as needed and mark the end
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  • For search, traverse the trie and check if the end node is marked as end of word
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  • For prefix search, traverse the trie and return true if you can complete the prefix path
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Steps to solve by this approach:

 Step 1: Create a TrieNode class with children object and isEndOfWord boolean flag.

 Step 2: Initialize the Trie with a root node.

 Step 3: For insertion, traverse character by character, creating new nodes if they don't exist.

 Step 4: Mark the final node as end of word after inserting all characters.

 Step 5: For search, traverse the path and check if final node is marked as end of word.

 Step 6: For prefix search, traverse the prefix path and return true if path exists.

 Step 7: Handle edge cases like empty strings and non-existent paths.

Submitted Code :