Tutorialspoint
Problem
Solution
Submissions
Back

Search Autocomplete System

Certification: Intermediate Level Accuracy: 0% Submissions: 0 Points: 15

Design a search autocomplete system that supports the following operations:

Example 1
    

  • Input: ["AutocompleteSystem", "input", "input", "input", "input"]

    [[["i love you", "island", "iroman", "i love leetcode"], [5, 3, 2, 2]], ["i"], [" "], ["a"], ["#"]]
    • 

  • Output: [null, ["i love you", "island", "i love leetcode"], ["i love you", "i love leetcode"], [], []]
    • 

  • Explanation: 
      

    • Step 1: Initialize the system with sentences ["i love you", "island", "iroman", "i love leetcode"] and their frequencies [5, 3, 2, 2].
      • 

    • Step 2: User inputs 'i'. System returns ["i love you", "island", "i love leetcode"] sorted by frequency.
      • 

    • Step 3: User inputs ' '. System returns ["i love you", "i love leetcode"] with the prefix "i ".
      • 

    • Step 4: User inputs 'a'. No sentences have the prefix "i a", so return [].
      • 

    • Step 5: User inputs '#' which indicates the end of a search. System records "i a" but returns [].
      • 

    

    •
Example 2
    

  • Input: ["AutocompleteSystem", "input", "input", "input", "input", "input"]
     [[["hello world", "hello python", "coding is fun"], [5, 4, 3]], ["h"], ["e"], ["l"], ["l"], ["o"]]
    • 

  • Output: [null, ["hello world", "hello python"], ["hello world", "hello python"], ["hello world", "hello python"], ["hello world", "hello python"], ["hello world", "hello python"]]
    • 

  • Explanation: 
      

    • Step 1: Initialize the system with sentences ["hello world", "hello python", "coding is fun"] and their frequencies [5, 4, 3].
      • 

    • Step 2: User inputs 'h'. System returns ["hello world", "hello python"] sorted by frequency.
      • 

    • Step 3: User inputs 'e'. System returns ["hello world", "hello python"] with prefix "he".
      • 

    • Step 4: User inputs 'l'. System returns ["hello world", "hello python"] with prefix "hel".
      • 

    • Step 5: User inputs 'l'. System returns ["hello world", "hello python"] with prefix "hell".
      • 

    • Step 6: User inputs 'o'. System returns ["hello world", "hello python"] with prefix "hello".
      • 

    

    •
Constraints
    

  • The input sentences contain only lowercase English letters, spaces, and special characters like '#'.
    • 

  • 1 ≤ sentences.length ≤ 100
    • 

  • 1 ≤ sentences[i].length ≤ 100
    • 

  • 1 ≤ times[i] ≤ 50
    • 

  • 1 ≤ input.length ≤ 1000
    • 

  • The character '#' marks the end of a search query.
    • 

  • Time Complexity: Constructor O(k*l), Input O(p + q + mlog(m))
    • 

  • Space Complexity: O(k*l)
    •
Trie Data StructureKPMGSamsung
Editorial

Login to view the detailed solution and explanation for this problem.

My Submissions
All Solutions
Refresh
Lang Status Date Code
You do not have any submissions for this problem.
Refresh
User Lang Status Date Code
No submissions found.

Please Login to continue
Solve Problems

 
 
 
Output Window
Clear All Apply Filters

Trending

Others

SIGN IN

Don't have an account? Register

Hint
Solution

Solution Hints

    
    
  • Use a Trie data structure to efficiently store and search for sentences with a given prefix.
    • 
    
  • Each Trie node should store a map of all sentences passing through that node along with their frequencies.
    • 
    
  • Implement a priority queue or sorting mechanism to retrieve the top k matching sentences by frequency.
    • 
    
  • Handle the special character '#' to indicate the end of a sentence and update its frequency.
    • 
    
  • For efficient storage and retrieval, consider using a combination of a Trie and a HashMap.
    •

Steps to solve by this approach:

 Step 1: Design a Trie data structure where each node contains a map of children nodes and a map of sentences with their frequencies

 Step 2: Initialize the system by adding all the sentences to the Trie, updating frequencies at each character node

 Step 3: For each input character, append it to the current input string and find the corresponding Trie node

 Step 4: Retrieve all sentences and their frequencies from the current node

 Step 5: Sort the sentences by frequency (descending) and then lexicographically, and return the top 3 results

Submitted Code :