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FlashkyFlashky
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feat: solve day 13
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5 files changed

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‎src/main/java/com/adventofcode/flashk/day13/ClawContraption.java‎

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package com.adventofcode.flashk.day13;
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import java.util.ArrayList;
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import java.util.List;
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public class ClawContraption {
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private List<Machine> machines = new ArrayList<>();
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public ClawContraption(List<String> inputs) {
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for(int i = 0; i < inputs.size(); i += 4) {
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machines.add(new Machine(inputs.get(i), inputs.get(i + 1), inputs.get(i + 2)));
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}
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}
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public long solveA() {
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return machines.stream().map(Machine::optimize).filter(m -> m != -1).reduce(0L, Long::sum);
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}
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public long solveB() {
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return machines.stream().map(Machine::optimizeB).filter(m -> m != -1).reduce(0L, Long::sum);
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}
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}

‎src/main/java/com/adventofcode/flashk/day13/Machine.java‎

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package com.adventofcode.flashk.day13;
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import com.adventofcode.flashk.common.Vector2;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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public class Machine {
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private static final Pattern BUTTONS_PATTERN = Pattern.compile("X\\+(\\d*), Y\\+(\\d*)");
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private static final Pattern PRIZE_PATTERN = Pattern.compile("X=(\\d*), Y=(\\d*)");
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private static final int TOKENS_A = 3;
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private static final int TOKENS_B = 1;
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private final Vector2 buttonA;
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private final Vector2 buttonB;
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private final Vector2 prizePosition;
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private final long prizePositionBX;
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private final long prizePositionBY;
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public Machine(String buttonA, String buttonB, String prize){
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this.buttonA = initializeVector(buttonA);
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this.buttonB = initializeVector(buttonB);
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this.prizePosition = initializeVector(prize);
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this.prizePositionBX = prizePosition.getX() + 10000000000000L;
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this.prizePositionBY = prizePosition.getY() + 10000000000000L;
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}
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private Vector2 initializeVector(String entry) {
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if(entry.startsWith("Button")) {
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Matcher matcher = BUTTONS_PATTERN.matcher(entry);
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if(matcher.find()){
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int xPos = Integer.parseInt(matcher.group(1));
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int yPos = Integer.parseInt(matcher.group(2));
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return new Vector2(xPos, yPos);
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}
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} else if(entry.startsWith("Prize")) {
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Matcher matcher = PRIZE_PATTERN.matcher(entry);
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if(matcher.find()){
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int xPos = Integer.parseInt(matcher.group(1));
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int yPos = Integer.parseInt(matcher.group(2));
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return new Vector2(xPos, yPos);
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}
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}
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throw new IllegalArgumentException("Invalid entry");
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}
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public void testMovement() {
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Vector2 initialPosition = new Vector2(0, 0);
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Vector2 finalPositionA = new Vector2(80 * buttonA.getX(), 80 * buttonA.getY());
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Vector2 finalPositionB = new Vector2(40 * buttonB.getX(), 40 * buttonB.getY());
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initialPosition.transform(finalPositionA);
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initialPosition.transform(finalPositionB);
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}
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public long optimize() {
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int minTokens = Integer.MAX_VALUE;
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for(int buttonAPresses = 0; buttonAPresses <= 100; buttonAPresses++) {
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for(int buttonBPresses = 0; buttonBPresses <= 100; buttonBPresses++) {
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Vector2 initialPosition = new Vector2(0, 0);
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Vector2 finalPositionA = new Vector2(buttonAPresses * buttonA.getX(), buttonAPresses * buttonA.getY());
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Vector2 finalPositionB = new Vector2(buttonBPresses * buttonB.getX(), buttonBPresses * buttonB.getY());
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initialPosition.transform(finalPositionA);
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initialPosition.transform(finalPositionB);
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if(initialPosition.equals(prizePosition)) {
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int tokens = buttonAPresses * TOKENS_A + buttonBPresses * TOKENS_B;
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minTokens = Math.min(minTokens, tokens);
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}
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}
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}
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return minTokens != Integer.MAX_VALUE ? minTokens : -1;
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}
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public long optimizeB() {
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// Ecuación lineal con dos incógnitas
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long axpy = buttonA.getX() * prizePositionBY;
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long aypx = buttonA.getY() * prizePositionBX;
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long axby = (long) buttonA.getX() * buttonB.getY();
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long aybx = (long) buttonA.getY() * buttonB.getX();
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long b = (axpy - aypx) / (axby - aybx);
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long a = (prizePositionBX - b * buttonB.getX()) / buttonA.getX();
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long posX = a * buttonA.getX() + b * buttonB.getX();
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long posY = a * buttonA.getY() + b * buttonB.getY();
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if(posX == prizePositionBX && posY == prizePositionBY) {
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return a * TOKENS_A + b * TOKENS_B;
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} else {
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return -1;
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}
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}
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}

‎src/main/java/com/adventofcode/flashk/day13/README.md‎

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# Day 13:
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# Day 13: Claw Contraption
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[https://adventofcode.com/2024/day/13](https://adventofcode.com/2024/day/13)

‎src/test/java/com/adventofcode/flashk/day13/Day13Test.java‎

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@DisplayName(TestDisplayName.DAY_13)
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@TestMethodOrder(OrderAnnotation.class)
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@Disabled // TODO Remove comment when implemented
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public class Day13Test extends PuzzleTest {
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private static final String INPUT_FOLDER = TestFolder.DAY_13;
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// Read input file
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List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE_SAMPLE);
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assertEquals(0L,0L);
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ClawContraption clawContraption = new ClawContraption(inputs);
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assertEquals(480L,clawContraption.solveA());
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}
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@Test
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// Read input file
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List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE);
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ClawContraption clawContraption = new ClawContraption(inputs);
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System.out.println("Solution: ");
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assertEquals(0L,0L);
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assertEquals(29877L,clawContraption.solveA());
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}
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// Read input file
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List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE_SAMPLE);
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ClawContraption clawContraption = new ClawContraption(inputs);
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// There is no example for this part
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assertEquals(0L,0L);
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}
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// Read input file
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List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE);
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ClawContraption clawContraption = new ClawContraption(inputs);
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System.out.println("Solution: ");
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assertEquals(0L,0L);
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assertEquals(99423413811305L,clawContraption.solveB());
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}
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‎src/test/resources/inputs‎

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