* The height of the node is the maximal number of edges between a sink node in
* that block and the node itself (plus 1).
* @param h The heights object.
* The height of the node is the maximal number of edges between a sink node in
* that block and the node itself (plus 1).
* @param h The heights object.
* from another node. Both nodes must be in the same block.
* @param h The heights object.
* @param n The first node.
* from another node. Both nodes must be in the same block.
* @param h The heights object.
* @param n The first node.