Day13.java

package com.sbaars.adventofcode.year19.days;

import com.sbaars.adventofcode.year19.Day2019;
import com.sbaars.adventofcode.year19.intcode.IntcodeComputer;

import java.awt.*;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;

public class Day13 extends Day2019 {
  public Day13() {
    super(13);
  }

  public static void main(String[] args) {
    new Day13().printParts();
  }

  @Override
  public Object part1() {
    IntcodeComputer cp = new IntcodeComputer(13);
    Set<Point> n = new HashSet<Point>();
    while (true) {
      long x = cp.run();
      if (x == IntcodeComputer.STOP_CODE) return n.size();
      long y = cp.run();
      long tile = cp.run();
      if (tile == 2)
        n.add(new Point(Math.toIntExact(x), Math.toIntExact(y)));
    }
  }

  @Override
  public Object part2() {
    IntcodeComputer cp = new IntcodeComputer(13, 1);
    cp.setElement(0, 2);
    int[][] field = new int[21][38];
    int score = 0;
    AtomicInteger paddlePos = new AtomicInteger(), ballPos = new AtomicInteger();
    while (true) {
      long x = cp.run();
      if (x == IntcodeComputer.STOP_CODE)
        return score;
      long y = cp.run();
      long tile = cp.run();
      score = simulateField(cp, field, score, paddlePos, ballPos, Math.toIntExact(x), Math.toIntExact(y), Math.toIntExact(tile));
    }
  }

  private int simulateField(IntcodeComputer cp, int[][] field, int score, AtomicInteger paddlePos, AtomicInteger ballPos, int x, int y, int tile) {
    if (x == -1)
      return tile;
    else {
      field[y][x] = tile;
      if (tile == 3) {
        paddlePos.set(x);
      } else if (tile == 4) {
        ballPos.set(x);
        cp.setInput(provideInput(paddlePos, ballPos));
      }
    }
    return score;
  }

  private int provideInput(AtomicInteger paddlePos, AtomicInteger ballPos) {
    int ball = ballPos.get(), paddle = paddlePos.get();
    return Integer.compare(ball, paddle);
  }
}