code: public IAtomContainer getSpanningTree() {
          IAtomContainer container = molecule.getBuilder().newInstance(IAtomContainer.class);
          for (int a = 0; a < totalVertexCount; a++)
              container.addAtom(molecule.getAtom(a));
          for (int b = 0; b < totalEdgeCount; b++)
              if (bondsInTree[b]) container.addBond(molecule.getBond(b));
          return container;
      }
docs: Access the computed spanning tree of the input molecule.
  
  @return acyclic tree of the input molecule