studio.kdb.Sorter Maven / Gradle / Ivy

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package studio.kdb;

import java.util.Arrays;
import java.util.Comparator;

public class Sorter {

    public static int[] sort(K.KBaseVector array, int[] origIndex) {
        Integer[] index = new Integer[array.getLength()];
        for (int i=0; i indexComparator = new IndexComparator(array);
        Comparator origIndexComparator = new OrigIndexComparator(origIndex);
        Arrays.sort(index, indexComparator.thenComparing(origIndexComparator));
        int[] res = new int[array.getLength()];
        for (int i=0; i array, int[] origIndex) {
        int count = origIndex.length;
        int[] res = new int[count];
        if (count == 0) return res;

        K.KBase current = array.at(origIndex[count-1]);
        int currentStart = 0;

        for (int i=1; ; i++) {
            K.KBase next = i == count ? null : array.at(origIndex[count-i-1]);

            if (next == null || next.compareTo(current) != 0) {
                System.arraycopy(origIndex, count - (i-1) - 1, res, currentStart, i - currentStart );
                if (next == null) break;
                current = next;
                currentStart = i;
            }
        }
        return res;
    }

    private static class IndexComparator implements Comparator {
        private K.KBaseVector array;

        IndexComparator(K.KBaseVector array) {
            this.array = array;
        }

        @Override
        public int compare(Integer i1, Integer i2) {
            return array.at(i1).compareTo(array.at(i2));
        }
    }

    private static int[] inverse(int[] index) {
        int[] res = new int[index.length];
        for (int i=0; i {
        private int[] index;
        OrigIndexComparator(int[] index) {
            this.index = inverse(index);
        }

        @Override
        public int compare(Integer i1, Integer i2) {
            return index[i1] - index[i2];
        }
    }

}