class SparseVector extends Vector {

    @Override
    public double get(int i) {
        int pos = Arrays.binarySearch(indices, i);
        if (pos >= 0) {
            return values[pos];
        }
        return 0.;
    }

    public  SparseVector();
    public  SparseVector(int n);
    public  SparseVector(int n, int[] indices, double[] values);
    public  SparseVector(int n, Map<Integer, Double> kv);

}