Fix assertion

bnb/edmonds_karp.cpp

@@ -7,7 +7,7 @@
 edmonds_karp::edmonds_karp(const graph &g, node_id source, node_id sink) 
     : g(g), source(source), sink(sink) {
 	assert(source > 0); // Nodes have ids: 1, .., n
-	assert(source < g.num_nodes());
+	assert(source <= g.num_nodes());
 };
 
 /* Indexes edges of the graph
@@ -132,4 +132,4 @@ void edmonds_karp::run() {
 
 int edmonds_karp::get_max_flow() const {
     return flow_value;
-};
\ No newline at end of file
+};