adventofcode/src/main/java/AoC2016_04.java at main · pareronia/adventofcode · GitHub

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import static com.github.pareronia.aoc.AssertUtils.assertTrue;

import static com.github.pareronia.aoc.Utils.toAString;

import static java.util.Comparator.comparing;

import java.util.List;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import com.github.pareronia.aoc.Counter;

import com.github.pareronia.aoc.Counter.Entry;

import com.github.pareronia.aoc.StringOps;

import com.github.pareronia.aoc.Utils;

import com.github.pareronia.aoc.solution.Sample;

import com.github.pareronia.aoc.solution.Samples;

import com.github.pareronia.aoc.solution.SolutionBase;

public class AoC2016_04

extends SolutionBase<List<AoC2016_04.Room>, Integer, Integer> {

private static final Pattern REGEXP = Pattern.compile("([-a-z]+)-([0-9]+)\\[([a-z]{5})\\]$");

private static final Pattern MATCH = Pattern.compile("[a-z]{9}-[a-z]{6}-[a-z]{7}$");

private AoC2016_04(final boolean debug) {

super(debug);

}

public static final AoC2016_04 create() {

return new AoC2016_04(false);

}

public static final AoC2016_04 createDebug() {

return new AoC2016_04(true);

}

@Override

protected List<Room> parseInput(final List<String> inputs) {

return inputs.stream().map(Room::fromInput).toList();

}

@Override

public Integer solvePart1(final List<Room> rooms) {

return rooms.stream()

.filter(Room::isReal)

.mapToInt(Room::sectorId)

.sum();

}

@Override

public Integer solvePart2(final List<Room> rooms) {

return rooms.stream()

.filter(r -> MATCH.matcher(r.name()).matches())

.filter(r -> r.decrypt().equals("northpole object storage"))

.map(Room::sectorId)

.findFirst().orElseThrow();

}

@Samples({

@Sample(method = "part1", input = TEST, expected = "1514")

})

public static void main(final String[] args) throws Exception {

AoC2016_04.create().run();

}

private static final String TEST = """

aaaaa-bbb-z-y-x-123[abxyz]

a-b-c-d-e-f-g-h-987[abcde]

not-a-real-room-404[oarel]

totally-real-room-200[decoy]

""";

record Room(String name, int sectorId, String checkum) {

public static Room fromInput(final String line) {

final Matcher m = REGEXP.matcher(line);

assertTrue(m.matches(), () -> "Expected match");

return new Room(m.group(1), Integer.parseInt(m.group(2)), m.group(3));

}

public boolean isReal() {

return new Counter<>(

Utils.asCharacterStream(this.name.replace("-", "")))

.mostCommon().stream()

.sorted(comparing(e -> e.count() * -100 + e.value().charValue()))

.limit(5)

.map(Entry::value)

.collect(toAString())

.equals(this.checkum);

}

private Character decrypt(final Character c, final int shift) {

if (c == '-') {

return ' ';

}

return StringOps.nextLetter(c, shift);

}

public String decrypt() {

final int shift = this.sectorId % 26;

return Utils.asCharacterStream(this.name)

.map(c -> decrypt(c, shift))

.collect(toAString());

}

adventofcode/src/main/java/AoC2016_04.java at main · pareronia/adventofcode · GitHub

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