HDT — Hierarchical Depth Traversal — coarsens the molecular graph into communities and serializes the resulting hierarchy with a single depth-first walk, so cross-community edges become ordinary back-edges in the token stream.
Watch HDT build a molecule token-by-token. Root → community partitions → atoms. Solid orange curves are intra-community graph edges; dashed orange curves are cross-community edges (still encoded as back-edges during the DFS, with no separate wiring section). Black arrows trace the DFS traversal order.