docs: protected static void nearestMeans(double[][] cdist, int[][] cnum) {
      final int k = cdist.length;
      double[] buf = new double[k - 1];
      for(int i = 0; i < k; i++) {
        System.arraycopy(cdist[i], 0, buf, 0, i);
        System.arraycopy(cdist[i], i + 1, buf, i, k - i - 1);
        for(int j = 0; j < buf.length; j++) {
          cnum[i][j] = j < i ? j : (j + 1);
        }
        DoubleIntegerArrayQuickSort.sort(buf, cnum[i], k - 1);
      }
    }