Added the method to find the isolated nodes in the graph

graphs/basic_graphs.py

@@ -279,3 +279,12 @@ def krusk(E_and_n):
                 s[j].update(s[i])
                 s.pop(i)
                 break
+
+
+# find the isolated node in the graph
+def find_isolated_nodes(graph):
+    isolated = []
+    for node in graph:
+        if not graph[node]:
+            isolated.append(node)
+    return isolated