Package g1001_1100.s1032_stream_of_characters

Class StreamChecker

java.lang.Object
g1001_1100.s1032_stream_of_characters.StreamChecker
public class StreamChecker extends java.lang.Object
1032 - Stream of Characters.

Hard

Design an algorithm that accepts a stream of characters and checks if a suffix of these characters is a string of a given array of strings words.

For example, if words = ["abc", "xyz"] and the stream added the four characters (one by one) 'a', 'x', 'y', and 'z', your algorithm should detect that the suffix "xyz" of the characters "axyz" matches "xyz" from words.

Implement the StreamChecker class:

  • StreamChecker(String[] words) Initializes the object with the strings array words.
  • boolean query(char letter) Accepts a new character from the stream and returns true if any non-empty suffix from the stream forms a word that is in words.

Example 1:

Input [“StreamChecker”, “query”, “query”, “query”, “query”, “query”, “query”, “query”, “query”, “query”, “query”, “query”, “query”] ["cd", "f", "kl", [“a”], [“b”], [“c”], [“d”], [“e”], [“f”], [“g”], [“h”], [“i”], [“j”], [“k”], [“l”]]

Output: [null, false, false, false, true, false, true, false, false, false, false, false, true]

Explanation:

 StreamChecker streamChecker = new StreamChecker(["cd", "f", "kl"]); 
 streamChecker.query("a"); // return False 
 streamChecker.query("b"); // return False 
 streamChecker.query("c"); // return False 
 streamChecker.query("d"); // return True, because 'cd' is in the wordlist 
 streamChecker.query("e"); // return False 
 streamChecker.query("f"); // return True, because 'f' is in the wordlist 
 streamChecker.query("g"); // return False 
 streamChecker.query("h"); // return False 
 streamChecker.query("i"); // return False 
 streamChecker.query("j"); // return False 
 streamChecker.query("k"); // return False 
 streamChecker.query("l"); // return True, because 'kl' is in the wordlist

Constraints:

  • 1 <= words.length <= 2000
  • 1 <= words[i].length <= 2000
  • words[i] consists of lowercase English letters.
  • letter is a lowercase English letter.
  • At most 4 * 104 calls will be made to query.

  • Constructor Summary

    Constructors
    Constructor
    Description
    StreamChecker(java.lang.String[] words)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    insert(java.lang.String s)
     
    boolean
    query(char letter)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • StreamChecker

      public StreamChecker(java.lang.String[] words)

  • Method Details

    • insert

      public void insert(java.lang.String s)

    • query

      public boolean query(char letter)