Explanation of the Java code for Wordle comparison

This code defines a class named WordleComparison that simulates Wordle gameplay and displays the color-coded result for each guess compared to the answer.

1. Imports and Class Definition:

• java.util.List: Used to hold a collection of word pairs.
• java.util.stream.Collectors: Used to collect results from streams.
• java.util.stream.Stream: Used to generate a stream of elements.

2. Main Method:

• Creates a list of TwoWords objects, each containing an answer and a guess.
• Iterates through the list and prints the answer, guess, and the result of comparing them using the wordle method.

3. wordle Method:

• Takes the answer and guess strings as input.
• Checks if the lengths are equal, throwing an assertion error if not.
• Creates a copy of the answer string to avoid modifying the original.
• Initializes a list of Colour enums with the same length as the words, all set to GREY.
• Iterates through each character in the guess:
  • If the character matches the corresponding character in the answer:
    • Replaces the matched character in the answer copy with a special character (NULL) to avoid matching it again.
    • Sets the color of the guess character in the result list to GREEN.
• Iterates through each character in the guess again:
  • If the character exists in the remaining answer copy (excluding matched characters):
    • Replaces the first occurrence of the character in the answer copy with NULL.
    • Sets the color of the guess character in the result list to YELLOW.
• Returns the final list of colors representing the comparison result.

4. Additional Elements:

• Colour enum: Defines the three possible colors (GREEN, GREY, YELLOW) used to represent the match status of each character in the guess.
• TwoWords record: Defines a record with two fields - answer and guess - to hold word pairs efficiently.
• NULL constant: Defines a special character (\0) used to mark matched characters in the answer copy to avoid repeating matches in the second loop.

Summary:

This code simulates the Wordle logic by comparing two strings (answer and guess) and assigns color codes based on the match status of each character:

• Green: Character is in the correct position and matches the answer.
• Yellow: Character is present in the answer but not in the correct position.
• Grey: Character is not present in the answer.

Step by Step solution about How to resolve the algorithm Wordle comparison step by step in the Java programming language

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public final class WordleComparison {

	public static void main(String[] args) {
		List<TwoWords> pairs = List.of( new TwoWords("ALLOW", "LOLLY"), new TwoWords("ROBIN", "SONIC"),
			new TwoWords("CHANT", "LATTE"), new TwoWords("We're", "She's"), new TwoWords("NOMAD", "MAMMA") );
		
		for ( TwoWords pair : pairs ) {
			System.out.println(pair.answer + " v " + pair.guess + " -> " + wordle(pair.answer, pair.guess));
		}
	}
	
	private static List<Colour> wordle(String answer, String guess) {
		final int guessLength = guess.length();
		if ( answer.length() != guessLength ) {
		    throw new AssertionError("The two words must be of the same length.");
		}
		
		String answerCopy = answer;
		List<Colour> result = Stream.generate( () -> Colour.GREY ).limit(guessLength).collect(Collectors.toList());
		for ( int i = 0; i < guessLength; i++ ) {
		    if ( answer.charAt(i) == guess.charAt(i) ) {
		        answerCopy = answerCopy.substring(0, i) + NULL + answerCopy.substring(i + 1);
		        result.set(i, Colour.GREEN);
		    }
		}
		
		for ( int i = 0; i < guessLength; i++ ) {
		    int index = answerCopy.indexOf(guess.charAt(i));
		    if ( index >= 0 ) {
		        answerCopy = answerCopy.substring(0, index) + NULL + answerCopy.substring(index + 1);
		        result.set(i, Colour.YELLOW);
		    }
		}
		return result;
	}
	
	private enum Colour { GREEN, GREY, YELLOW }
	
	private static record TwoWords(String answer, String guess) {}
	
	private static final char NULL = '\0';

}