class SparseMatrix extends Matrix {

  @Override
  public String toString() {
    final StringBuilder builder = new StringBuilder();
    builder.append(String.format("[%d x %d]", this.getRowCount(), this.getColumnCount()));

    this.forEach((r, c, v) -> builder.append(formatEntry(r, c, v)));
    return builder.toString();
  }

  public  SparseMatrix(final int numRows, final int numCols, final int initialCapacityPerRow);

}