added a jank component set check

Author: Gillgamesh

include/test/graph_verifier.h

@@ -61,6 +61,13 @@ class GraphVerifier {
    */
   void verify_connected_components(const ConnectedComponents &cc);
 
+  /**
+   * Verifies the connected components solution is correct. Compares
+   * retval against kruskal_ref.
+   * @throws IncorrectCCException if the solution cannot be verified
+   */
+  void verify_cc_from_component_set(std::vector<std::set<node_id_t>> component_set);
+
   /**
    * Verifies that one or more spanning forests are valid
    * Additionally, enforces that spanning forests must be edge disjoint.

test/util/graph_verifier.cpp

@@ -106,6 +106,26 @@ void GraphVerifier::verify_connected_components(const ConnectedComponents &cc) {
   }
 }
 
+void GraphVerifier::verify_cc_from_component_set(std::vector<std::set<node_id_t>> component_set) {
+  // compute the connected components for the verifier
+  kruskal();
+
+  // first check that the number of components is the same for both
+  if (kruskal_ccs != component_set.size()) {
+    throw IncorrectCCException("Incorrect number of components!");
+  }
+  // then check that we agree on where all the vertices belong
+  for (auto &component : component_set) {
+    node_id_t first = *component.begin();
+    node_id_t root = kruskal_dsu.find_root(first);
+    for (auto &node : component) {
+      if (kruskal_dsu.find_root(node) != root) {
+        throw IncorrectCCException("Incorrect Connectivity!");
+      }
+    }
+  }
+}
+
 void GraphVerifier::verify_spanning_forests(std::vector<SpanningForest> SFs) {
   // backup the adjacency matrix
   std::vector<std::vector<bool>> backup(adj_matrix);