Instances are all written under the same format:
* On the first line, the number of nodes.
* Then for each node, one line with node_id followed by two columns ":" and the id of all nodes to which the node connects (has an edge with).

The format is the same as for generated graphs BarabasiAlbert{500,1000,2500,5000}, ErdosRenyi{250,500,1000,2500}, ForestFire{250,500,1000,2000} and WattsStrogatz{250,500,1000,1500} that can be found at the following url: https://engineering.purdue.edu/~mventresca/cnd.zip