86 lines
2.4 KiB
Java
86 lines
2.4 KiB
Java
import java.util.Arrays;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.Map;
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import java.util.Optional;
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import java.util.stream.Collectors;
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import java.util.stream.IntStream;
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public interface StemAndLeaf {
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public static final int[] data = {12, 127, 28, 42, 39, 113, 42, 18, 44, 118,
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44, 37, 113, 124, 37, 48, 127, 36, 29, 31, 125, 139, 131, 115, 105,
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132, 104, 123, 35, 113, 122, 42, 117, 119, 58, 109, 23, 105, 63,
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27, 44, 105, 99, 41, 128, 121, 116, 125, 32, 61, 37, 127, 29, 113,
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121, 58, 114, 126, 53, 114, 96, 25, 109, 7, 31, 141, 46, 13, 27,
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43, 117, 116, 27, 7, 68, 40, 31, 115, 124, 42, 128, 52, 71, 118,
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117, 38, 27, 106, 33, 117, 116, 111, 40, 119, 47, 105, 57, 122,
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109, 124, 115, 43, 120, 43, 27, 27, 18, 28, 48, 125, 107, 114, 34,
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133, 45, 120, 30, 127, 31, 116, 146};
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public static Map<Integer, List<Integer>> createPlot(int... data) {
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Map<Integer, List<Integer>> plot = Arrays.stream(data)
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.parallel()
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.boxed()
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.collect(
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Collectors.groupingBy(
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datum -> datum / 10, // stem, integer division
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Collectors.mapping(
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datum -> datum % 10, // leaf
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Collectors.toList()
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)
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)
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)
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;
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int highestStem = Arrays.stream(data)
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.parallel()
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.map(datum -> datum / 10)
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.max()
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.orElse(-1) //for filling in stems with no leaves
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;
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Optional.of(plot)
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.map(Map::keySet)
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.map(Collection::size)
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.filter(size -> size < highestStem + 1 /*highest stem value and 0*/)
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.ifPresent(p ->
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IntStream.rangeClosed(
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0,
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highestStem
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)
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.parallel()
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.forEach(i ->
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plot.computeIfAbsent(i, $ -> new LinkedList<>())
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)
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)
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;
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return plot;
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}
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public static void printPlot(Map<Integer, List<Integer>> plot) {
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plot.entrySet()
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.stream()
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.parallel()
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.peek(line -> Optional.of(line)
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.map(Map.Entry::getValue)
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.ifPresent(Collections::sort)
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)
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.map(line ->
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String.join(" ",
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String.valueOf(line.getKey()),
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"|",
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String.valueOf(line.getValue())
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)
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)
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.forEachOrdered(System.out::println)
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;
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}
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public static void main(String... arguments) {
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Optional.of(data)
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.map(StemAndLeaf::createPlot)
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.ifPresent(StemAndLeaf::printPlot)
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;
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}
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}
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