Fixed overflow error

bnb/edmonds_karp.cpp

@@ -41,7 +41,7 @@ std::pair<int, node_id> edmonds_karp::bfs(std::vector<int> &resid_flow, std::vec
 
 	pred.clear();
 	pred.resize(g_.num_nodes() + 1, -1); // undiscovered nodes are marked with -1
-	std::vector<int> gain(g_.num_nodes(), 0);
+	std::vector<int> gain(g_.num_nodes() + 1, 0);
 	bool sink_reached = false;
 	node_id sink;