improved artsiomkorzun solution
This commit is contained in:
Artsiom Korzun
Gunnar Morling
parent
a53549ae50
commit
cec579b506
@ -17,4 +17,6 @@
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JAVA_OPTS="-XX:+UseParallelGC"
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source "$HOME/.sdkman/bin/sdkman-init.sh"
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sdk use java 21.0.1-graal 1>&2
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time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_artsiomkorzun
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@ -24,70 +24,51 @@ import java.nio.file.Path;
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import java.nio.file.StandardOpenOption;
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import java.util.Arrays;
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import java.util.Comparator;
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import java.util.concurrent.atomic.AtomicInteger;
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import java.util.concurrent.atomic.AtomicReference;
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import java.util.function.Consumer;
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import java.util.stream.IntStream;
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public class CalculateAverage_artsiomkorzun {
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private static final Path FILE = Path.of("./measurements.txt");
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private static final long FILE_SIZE = size(FILE);
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private static final int PARALLELISM = Runtime.getRuntime().availableProcessors();
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private static final int SEGMENT_SIZE = 16 * 1024 * 1024;
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private static final int SEGMENT_COUNT = (int) ((FILE_SIZE + SEGMENT_SIZE - 1) / SEGMENT_SIZE);
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private static final int SEGMENT_OVERLAP = 1024;
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public static void main(String[] args) throws Exception {
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/*
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* for (int i = 0; i < 10; i++) {
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* long start = System.currentTimeMillis();
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* execute();
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* long end = System.currentTimeMillis();
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* System.err.println("Time: " + (end - start));
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* }
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*/
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// for (int i = 0; i < 10; i++) {
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// long start = System.currentTimeMillis();
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// execute();
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// long end = System.currentTimeMillis();
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// System.err.println("Time: " + (end - start));
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// }
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execute();
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}
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private static void execute() {
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Aggregates aggregates = IntStream.range(0, SEGMENT_COUNT)
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.parallel()
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.mapToObj(CalculateAverage_artsiomkorzun::aggregate)
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.reduce(new Aggregates(), CalculateAverage_artsiomkorzun::merge)
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.sort();
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private static void execute() throws Exception {
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AtomicInteger counter = new AtomicInteger();
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AtomicReference<Aggregates> result = new AtomicReference<>();
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Aggregator[] aggregators = new Aggregator[PARALLELISM];
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for (int i = 0; i < aggregators.length; i++) {
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aggregators[i] = new Aggregator(counter, result);
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aggregators[i].start();
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}
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for (int i = 0; i < aggregators.length; i++) {
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aggregators[i].join();
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}
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Aggregates aggregates = result.get();
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aggregates.sort();
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print(aggregates);
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}
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private static Aggregates aggregate(int segment) {
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long position = (long) SEGMENT_SIZE * segment;
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int size = (int) Math.min(SEGMENT_SIZE + SEGMENT_OVERLAP, FILE_SIZE - position);
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int limit = Math.min(SEGMENT_SIZE, size - 1);
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MappedByteBuffer buffer = map(position, size); // leaking until gc
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if (position > 0) {
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next(buffer);
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}
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Aggregates aggregates = new Aggregates();
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Row row = new Row();
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while (buffer.position() <= limit) {
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parse(buffer, row);
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aggregates.add(row);
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}
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return aggregates;
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}
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private static Aggregates merge(Aggregates lefts, Aggregates rights) {
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Aggregates to = (lefts.size() < rights.size()) ? rights : lefts;
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Aggregates from = (lefts.size() < rights.size()) ? lefts : rights;
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from.visit(to::merge);
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return to;
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}
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private static void print(Aggregates aggregates) {
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StringBuilder builder = new StringBuilder(aggregates.size() * 15 + 32);
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builder.append("{");
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@ -111,62 +92,11 @@ public class CalculateAverage_artsiomkorzun {
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}
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}
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private static MappedByteBuffer map(long position, int size) {
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try (FileChannel channel = FileChannel.open(FILE, StandardOpenOption.READ)) {
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return channel.map(FileChannel.MapMode.READ_ONLY, position, size); // leaking until gc
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}
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catch (Throwable e) {
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throw new RuntimeException(e);
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}
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}
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private static void next(ByteBuffer buffer) {
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while (buffer.get() != '\n') {
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// continue
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}
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}
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private static void parse(ByteBuffer buffer, Row row) {
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int index = 0;
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byte b;
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while ((b = buffer.get()) != ';') {
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row.station[index++] = b;
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}
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row.length = index;
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double value = 0;
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double multiplier = 1;
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b = buffer.get();
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if (b == '-') {
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multiplier = -1;
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}
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else {
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assert b >= '0' && b <= '9';
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value = b - '0';
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}
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while ((b = buffer.get()) != '.') {
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assert b >= '0' && b <= '9';
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value = 10 * value + (b - '0');
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}
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b = buffer.get();
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assert b >= '0' && b <= '9';
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value = 10 * value + (b - '0');
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b = buffer.get();
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assert b == '\n';
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row.temperature = value * multiplier;
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}
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private static class Row {
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final byte[] station = new byte[256];
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int length;
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double temperature;
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int hash;
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int temperature;
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@Override
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public String toString() {
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@ -176,23 +106,25 @@ public class CalculateAverage_artsiomkorzun {
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private static class Aggregate implements Comparable<Aggregate> {
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final byte[] station;
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double min;
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double max;
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double sum;
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double count;
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final int hash;
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int min;
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int max;
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long sum;
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int count;
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public Aggregate(byte[] station, int length, double temperature) {
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this.station = Arrays.copyOf(station, length);
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this.min = temperature;
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this.max = temperature;
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this.sum = temperature;
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public Aggregate(Row row) {
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this.station = Arrays.copyOf(row.station, row.length);
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this.hash = row.hash;
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this.min = row.temperature;
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this.max = row.temperature;
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this.sum = row.temperature;
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this.count = 1;
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}
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public void add(double temperature) {
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min = Math.min(min, temperature);
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max = Math.max(max, temperature);
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sum += temperature;
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public void add(Row row) {
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min = Math.min(min, row.temperature);
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max = Math.max(max, row.temperature);
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sum += row.temperature;
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count++;
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}
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@ -223,7 +155,7 @@ public class CalculateAverage_artsiomkorzun {
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@Override
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public String toString() {
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return new String(station) + "=" + round(min) + "/" + round(sum / count) + "/" + round(max);
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return new String(station) + "=" + round(min) + "/" + round(1.0 * sum / count) + "/" + round(max);
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}
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private static double round(double v) {
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@ -255,26 +187,21 @@ public class CalculateAverage_artsiomkorzun {
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}
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public void add(Row row) {
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byte[] station = row.station;
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int length = row.length;
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double temperature = row.temperature;
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int hash = hash(station, length);
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int index = hash & (aggregates.length - 1);
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int index = row.hash & (aggregates.length - 1);
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while (true) {
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Aggregate aggregate = aggregates[index];
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if (aggregate == null) {
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aggregates[index] = new Aggregate(station, length, temperature);
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aggregates[index] = new Aggregate(row);
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if (++size >= limit) {
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grow();
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}
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break;
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}
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if (equal(station, length, aggregate.station, aggregate.station.length)) {
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aggregate.add(temperature);
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if (row.hash == aggregate.hash && Arrays.equals(row.station, 0, row.length, aggregate.station, 0, aggregate.station.length)) {
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aggregate.add(row);
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break;
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}
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@ -283,10 +210,7 @@ public class CalculateAverage_artsiomkorzun {
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}
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public void merge(Aggregate right) {
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byte[] station = right.station;
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int hash = hash(station, station.length);
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int index = hash & (aggregates.length - 1);
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int index = right.hash & (aggregates.length - 1);
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while (true) {
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Aggregate aggregate = aggregates[index];
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@ -299,7 +223,7 @@ public class CalculateAverage_artsiomkorzun {
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break;
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}
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if (equal(station, station.length, aggregate.station, aggregate.station.length)) {
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if (right.hash == aggregate.hash && Arrays.equals(right.station, aggregate.station)) {
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aggregate.merge(right);
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break;
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}
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@ -309,7 +233,7 @@ public class CalculateAverage_artsiomkorzun {
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}
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public Aggregates sort() {
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Arrays.parallelSort(aggregates, Comparator.nullsLast(Aggregate::compareTo));
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Arrays.sort(aggregates, Comparator.nullsLast(Aggregate::compareTo));
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return this;
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}
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@ -320,8 +244,7 @@ public class CalculateAverage_artsiomkorzun {
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for (Aggregate aggregate : oldAggregates) {
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if (aggregate != null) {
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int hash = hash(aggregate.station, aggregate.station.length);
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int index = hash & (aggregates.length - 1);
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int index = aggregate.hash & (aggregates.length - 1);
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while (aggregates[index] != null) {
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index = (index + 1) & (aggregates.length - 1);
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@ -331,29 +254,105 @@ public class CalculateAverage_artsiomkorzun {
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}
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}
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}
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}
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private static int hash(byte[] array, int length) {
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private static class Aggregator extends Thread {
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private final AtomicInteger counter;
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private final AtomicReference<Aggregates> result;
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public Aggregator(AtomicInteger counter, AtomicReference<Aggregates> result) {
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super("aggregator");
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this.counter = counter;
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this.result = result;
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}
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@Override
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public void run() {
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Aggregates aggregates = new Aggregates();
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Row row = new Row();
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try (FileChannel channel = FileChannel.open(FILE, StandardOpenOption.READ)) {
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for (int segment; (segment = counter.getAndIncrement()) < SEGMENT_COUNT;) {
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aggregate(channel, segment, aggregates, row);
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}
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}
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catch (Throwable e) {
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throw new RuntimeException(e);
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}
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while (!result.compareAndSet(null, aggregates)) {
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Aggregates rights = result.getAndSet(null);
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if (rights != null) {
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aggregates = merge(aggregates, rights);
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}
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}
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}
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private static void aggregate(FileChannel channel, int segment, Aggregates aggregates, Row row) throws Exception {
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long position = (long) SEGMENT_SIZE * segment;
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int size = (int) Math.min(SEGMENT_SIZE + SEGMENT_OVERLAP, FILE_SIZE - position);
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int limit = Math.min(SEGMENT_SIZE, size - 1);
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MappedByteBuffer buffer = channel.map(FileChannel.MapMode.READ_ONLY, position, size);
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if (position > 0) {
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next(buffer);
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}
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for (int offset = buffer.position(); offset <= limit;) {
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offset = parse(buffer, row, offset);
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aggregates.add(row);
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}
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}
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private static Aggregates merge(Aggregates lefts, Aggregates rights) {
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if (rights.size() < lefts.size()) {
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Aggregates temp = lefts;
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lefts = rights;
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rights = temp;
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}
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rights.visit(lefts::merge);
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return lefts;
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}
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private static void next(ByteBuffer buffer) {
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while (buffer.get() != '\n') {
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// continue
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}
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}
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private static int parse(ByteBuffer buffer, Row row, int offset) {
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byte[] station = row.station;
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int length = 0;
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int hash = 0;
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for (int i = 0; i < length; i++) {
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hash = 71 * hash + array[i];
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for (byte b; (b = buffer.get(offset++)) != ';';) {
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station[length++] = b;
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hash = 71 * hash + b;
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}
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return hash;
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row.length = length;
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row.hash = hash;
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int sign = 1;
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if (buffer.get(offset) == '-') {
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sign = -1;
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offset++;
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}
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private static boolean equal(byte[] left, int leftLength, byte[] right, int rightLength) {
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if (leftLength != rightLength) {
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return false;
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int value = buffer.get(offset++) - '0';
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if (buffer.get(offset) != '.') {
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value = 10 * value + buffer.get(offset++) - '0';
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}
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for (int i = 0; i < leftLength; i++) {
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if (left[i] != right[i]) {
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return false;
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}
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}
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return true;
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value = 10 * value + buffer.get(offset + 1) - '0';
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row.temperature = value * sign;
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return offset + 3;
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}
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}
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}
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