/**
* Search for an interference clique and an external node
* with affinity edges to all nodes of the clique.
* At most 1 node of the clique can be colored equally with the external node.
*/
/**
* Search for an interference clique and an external node
* with affinity edges to all nodes of the clique.
* At most 1 node of the clique can be colored equally with the external node.
*/