- graph = array bounds [(,) v (mapMaybe key_vertex ks) | (,) v (_, _, ks) <- edges1]
- key_map = array bounds [(,) v k | (,) v (_, k, _ ) <- edges1]
- vertex_map = array bounds edges1
+ graph = array bounds [ (v, mapMaybe key_vertex ks)
+ | (v, (_, _, ks)) <- edges1]
+ key_map = array bounds [ (v, k)
+ | (v, (_, k, _ )) <- edges1]
+ vertex_map = array bounds edges1