Update bnb.cpp

bnb/bnb.cpp

-
 #include <cassert>
 #include <iostream>
 
@@ -24,7 +23,7 @@ void assignment_state::assign(vertex_id node, partition_index p, std::vector<uns
 	assigned_partition_[node] = p;
 	//for each neighbor of node in other partitions: current_objective++
 	for(auto neighbor: neighbors){
-		if(assigned_partition_[neighbor] != 100 && assigned_partition_[neighbor] != p)
+		if(assigned_partition_[neighbor] == (p xor 1))
 			current_objective_++;
 	}
 	node_count[p]++;