Graph Format # comment graph (un)directed` <node-x> <node-y> [edge-weight] Example Graph File # Comment, ignored by graph reader graph directed n1 n2 2 n1 n3 4 n2 n3 1 n2 n4 4 n2 n5 2 n3 n5 3 n4 n6 2 n5 n4 3 n5 n6 2