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  1. import java.util.Arrays;
  2. import java.util.Random;
  3. import java.util.concurrent.ExecutionException;
  4. import java.util.concurrent.ExecutorService;
  5. import java.util.concurrent.Executors;
  6. import java.util.concurrent.Future;
  7. import java.util.stream.IntStream;
  8.  
  9. class MedianFilter {
  10.  
  11.     public static <T extends Comparable<T>> T[] getMedians(T[] data, int shoulder) {
  12.         T[] result = Arrays.copyOf(data, data.length);
  13.         IntStream.range(shoulder, data.length - shoulder).parallel().forEach(i -> result[i] = medianPoint(data, i, shoulder));
  14.         return result;
  15.     }
  16.  
  17.     private static <T extends Comparable<T>> T medianPoint(T[] data, int index, int shoulder) {
  18.         T[] window = Arrays.copyOfRange(data, index - shoulder, index + shoulder + 1);
  19.         if (window.length != (shoulder * 2 + 1)) {
  20.             throw new IllegalStateException("Illegal window size " + window.length);
  21.         }
  22.         Arrays.sort(window);
  23.         return window[shoulder];
  24.     }
  25.  
  26.     public static void main(String[] args) throws InterruptedException, ExecutionException {
  27.         Random rand = new Random(100);
  28.         Integer[] data = rand.ints(10, 0, 20).boxed().toArray(s -> new Integer[s]);
  29.         System.out.println(Arrays.toString(data));
  30.         System.out.println(Arrays.toString(getMedians(data, 4)));
  31.         Future<Integer[]> fut = medians(data, 4);
  32.         System.out.println(Arrays.toString(fut.get()));
  33.     }
  34.  
  35.     public static <T extends Comparable<T>> Future<T[]> medians(T[] data, int shoulder) {
  36.         ExecutorService service = Executors.newSingleThreadExecutor(r -> {
  37.             Thread t = new Thread(r);
  38.             t.setDaemon(true);
  39.             return t;
  40.         });
  41.  
  42.         Future<T[]> fut =  service.submit(() -> getMedians(data, shoulder));
  43.         service.shutdown();
  44.         return fut;
  45.     }
  46.  
  47. }
Success #stdin #stdout 0.24s 321728KB
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stdin
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Standard input is empty
stdout
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[15, 10, 14, 8, 11, 6, 16, 8, 3, 13]
[15, 10, 14, 8, 10, 10, 16, 8, 3, 13]
[15, 10, 14, 8, 10, 10, 16, 8, 3, 13]
https://ideone.com/3U6N79
language:
Java (HotSpot 12)
created:
8 years ago
visibility:
public

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