An unweighted directed graph is a data structure that extends Unweighted Graph by assuming all edges to be unidirectional by default. As a directed graph, once an edge between vertex A and B is set, it doesn't mean B will be connected to A as well, unless specifically set.
This data structure merely completes Unweighted Graph specification and defines no further operations. As a complete implementation, it must take a decision how to store vertexes inside. Options are same as those used in storing EDGES:
If Hash Table implementing Set solution is chosen, two more operations can be generalized for unweighted directed graph, both executed in constant O(1) time:
|contains||DATA||boolean||Checks if graph contains a vertex whose value equals that of input.|
|search||DATA||VERTEX||Searches graph for a vertex whose value equals that of input.|