Data update

Task/Wordiff/Java/wordiff.java

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+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Scanner;
+import java.util.stream.Collectors;
+
+public final class Wordiff {
+
+	public static void main(String[] args) throws IOException {
+		List<String> dictionary = Files.lines(Path.of("unixdict.txt")).toList();
+		List<String> starters = dictionary.stream()
+			.filter( word -> word.length() == 3 || word.length() == 4 ).collect(Collectors.toList());
+		Collections.shuffle(starters);
+		List<String> wordsUsed = new ArrayList<String>();
+		wordsUsed.add(starters.get(0));		
+		
+		Scanner scanner = new Scanner(System.in);
+		List<String> playerNames = requestPlayerNames(scanner);		
+		boolean playing = true;
+		int playerIndex = 0;
+		System.out.println("The first word is: " + wordsUsed.get(wordsUsed.size() -  1));		
+		
+		while ( playing ) {			
+			System.out.println(playerNames.get(playerIndex) + " enter your word: ");
+			String currentWord = scanner.nextLine();
+			if ( isWordiff(currentWord, wordsUsed, dictionary) ) {
+				wordsUsed.add(currentWord);
+				playerIndex = ( playerIndex == 0 ) ? 1 : 0;
+			} else {
+				System.out.println("You have lost the game, " + playerNames.get(playerIndex));
+				System.out.println("You could have entered: " + couldHaveEntered(wordsUsed, dictionary));
+				playing = false;
+			}			
+		}
+		scanner.close();
+	}	
+	
+	private static boolean isWordiff(String currentWord, List<String> wordsUsed, List<String> dictionary) {
+		if ( ! dictionary.contains(currentWord) || wordsUsed.contains(currentWord) ) {
+			return false;
+		}
+	
+		String previousWord = wordsUsed.get(wordsUsed.size() - 1);
+		return isLetterChanged(previousWord, currentWord)
+			|| isLetterRemoved(previousWord, currentWord) || isLetterAdded(previousWord, currentWord);
+	}
+	
+	private static boolean isLetterRemoved(String previousWord, String currentWord) {
+		for ( int i = 0; i < previousWord.length(); i++ ) {
+		    if ( currentWord.equals(previousWord.substring(0, i) + previousWord.substring(i + 1)) ) {
+		    	return true;
+		    }
+		}
+		return false;
+	}
+	
+	private static boolean isLetterAdded(String previousWord, String currentWord) {
+		return isLetterRemoved(currentWord, previousWord);
+	}
+
+	private static boolean isLetterChanged(String previousWord, String currentWord) {
+		if ( previousWord.length() != currentWord.length() ) {
+			return false;
+		}
+		
+		int differenceCount = 0;
+		for ( int i = 0; i < currentWord.length(); i++ ) {
+		    differenceCount += ( currentWord.charAt(i) == previousWord.charAt(i) ) ? 0 : 1;
+		}
+		return differenceCount == 1;
+	}	
+	
+	private static List<String> couldHaveEntered(List<String> wordsUsed, List<String> dictionary) {
+		List<String> result = new ArrayList<String>();		
+	    for ( String word : dictionary ) {
+		    if ( ! wordsUsed.contains(word) && isWordiff(word, wordsUsed, dictionary) ) {
+		        result.add(word);
+		    }
+	    }
+	    return result;
+	}
+	
+	private static List<String> requestPlayerNames(Scanner scanner) {
+		List<String> playerNames = new ArrayList<String>();
+		for ( int i = 0; i < 2; i++ ) {
+			System.out.print("Please enter the player's name: ");	
+			String playerName = scanner.nextLine().trim();
+			playerNames.add(playerName);
+		}
+	    return playerNames;
+	}
+
+}