71 lines
2.4 KiB
Java
71 lines
2.4 KiB
Java
/*
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* Copyright 2023 The original authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package dev.morling.onebrc;
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import java.io.IOException;
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import java.util.concurrent.*;
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import java.util.stream.Stream;
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import static java.nio.file.Files.lines;
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import static java.nio.file.Paths.*;
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public class CalculateAverage_abfrmblr {
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private static final String FILE = "./measurements.txt";
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private static record Stats (double min, double max, double mean, long count) {
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@Override
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public String toString() {
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return round(min) + "/" + round(mean) + "/" + round(max);
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}
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private double round(double value) {
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return Math.round(value * 10.0) / 10.0;
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}
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}
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private static record MeasurementTuple (String station, double temp) {
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public MeasurementTuple (String[] values) {
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this(values[0], Double.parseDouble(values[1]));
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}
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}
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public static void main(String[] args) throws IOException {
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Stream<String> lines = lines(get(FILE));
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ConcurrentMap<String, Stats> aggregatedStats = new ConcurrentSkipListMap<>();
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lines.parallel().forEach(s -> {
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MeasurementTuple tuple = new MeasurementTuple(s.split(";"));
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aggregatedStats.compute(tuple.station(), (s1, stats) -> {
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if (stats == null) {
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return new Stats(tuple.temp, tuple.temp, tuple.temp, 1L);
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}
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else {
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long latestCount = stats.count + 1;
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double min = Math.min(stats.min, tuple.temp);
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double max = Math.max(stats.max, tuple.temp);
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double mean = ((stats.mean * stats.count) + tuple.temp) / latestCount;
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return new Stats(min, max, mean, latestCount);
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}
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});
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});
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System.out.println(aggregatedStats);
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}
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}
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