adventofcode/src/main/java/AoC2016_20.java at main · pareronia/adventofcode · GitHub

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import static java.util.Comparator.comparing;

import static java.util.stream.Collectors.toList;

import com.github.pareronia.aoc.RangeInclusive;

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

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

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

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

@SuppressWarnings({"PMD.NoPackage", "PMD.ClassNamingConventions"})

public final class AoC2016_20 extends SolutionBase<List<RangeInclusive<Long>>, Long, Long> {

private static final long TOTAL_IPS = 4_294_967_296L;

private AoC2016_20(final boolean debug) {

super(debug);

}

public static AoC2016_20 create() {

return new AoC2016_20(false);

}

public static AoC2016_20 createDebug() {

return new AoC2016_20(true);

}

@Override

protected List<RangeInclusive<Long>> parseInput(final List<String> inputs) {

final List<RangeInclusive<Long>> ranges =

inputs.stream()

.map(s -> s.split("-"))

.map(sp -> RangeInclusive.between(Long.valueOf(sp[0]), Long.valueOf(sp[1])))

.collect(toList());

return combineRanges(ranges);

}

// TODO: unduplicate w/ RangeInclusive.mergeRanges

private List<RangeInclusive<Long>> combineRanges(final List<RangeInclusive<Long>> ranges) {

final List<RangeInclusive<Long>> combines = new ArrayList<>();

// why doesn't this work without sorting?

ranges.sort(comparing(RangeInclusive::getMinimum));

combines.add(ranges.get(0));

for (int i = 1; i < ranges.size(); i++) {

final RangeInclusive<Long> r = ranges.get(i);

boolean combined = false;

for (int j = 0; j < combines.size(); j++) {

final RangeInclusive<Long> combine = combines.get(j);

if (combine.isOverlappedBy(r)) {

final long min = Math.min(combine.getMinimum(), r.getMinimum());

final long max = Math.max(combine.getMaximum(), r.getMaximum());

combines.set(j, RangeInclusive.between(min, max));

combined = true;

} else if (r.getMaximum() + 1 == combine.getMinimum()) {

combines.set(j, RangeInclusive.between(r.getMinimum(), combine.getMaximum()));

combined = true;

} else if (combine.getMaximum() + 1 == r.getMinimum()) {

combines.set(j, RangeInclusive.between(combine.getMinimum(), r.getMaximum()));

combined = true;

}

if (!combined) {

combines.add(r);

}

return Collections.unmodifiableList(combines);

}

@Override

public Long solvePart1(final List<RangeInclusive<Long>> ranges) {

return ranges.stream().findFirst().map(c -> c.getMaximum() + 1).orElseThrow();

}

@Override

public Long solvePart2(final List<RangeInclusive<Long>> ranges) {

return ranges.stream()

.map(c -> c.getMaximum() - c.getMinimum() + 1)

.reduce(TOTAL_IPS, (a, b) -> a - b);

}

@Samples({

@Sample(method = "part1", input = TEST1, expected = "3"),

@Sample(method = "part1", input = TEST2, expected = "90000101"),

@Sample(method = "part2", input = TEST1, expected = "4294967288"),

@Sample(method = "part2", input = TEST2, expected = "4194967190"),

})

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

create().run();

}

private static final String TEST1 =

"""

5-8

0-2

4-7

""";

private static final String TEST2 =

"""

0-90000000

100000005-110000005

90000001-90000100

1000000054-1000000057

""";

}

adventofcode/src/main/java/AoC2016_20.java at main · pareronia/adventofcode · GitHub

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