Embodiments are directed to a computer implemented method of analyzing a graph having a plurality of vertices and edges to identify a subgraph of the graph, wherein the subgraph includes an exact subset. The method includes applying, by a first processor, a heuristic analysis to the graph to determine an initial subset of the graph. The method further includes applying, by either the first processor or a second processor, an exact analysis to the initial subset to determine an exact subset of the initial subset.