g1001_1100.s1032_stream_of_characters

Class StreamChecker

java.lang.Object

g1001_1100.s1032_stream_of_characters.StreamChecker

public class StreamChecker
extends 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 and Description
StreamChecker(String[] words)

Method Summary

Modifier and Type	Method and Description
void	insert(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 Detail

StreamChecker

public StreamChecker(String[] words)

Method Detail

insert

public void insert(String s)

query

public boolean query(char letter)