diff --git a/libs/util/include/psemek/util/dfs.hpp b/libs/util/include/psemek/util/dfs.hpp
index 5a1613ed..0956704a 100644
--- a/libs/util/include/psemek/util/dfs.hpp
+++ b/libs/util/include/psemek/util/dfs.hpp
@@ -20,20 +20,39 @@ namespace psemek::util
 
 		struct cycle_iterator
 		{
+			using iterator_category = std::forward_iterator_tag;
+			using value_type = Index;
+			using reference_type = Index;
+			using pointer = Index *;
+			using difference_type = int;
+
 			dfs * parent;
 			Index i;
 
 			Index operator *() const { return i; }
+
 			cycle_iterator & operator ++()
 			{
 				i = parent->parent_[i];
 				return *this;
 			}
 
+			cycle_iterator operator ++(int)
+			{
+				auto copy = *this;
+				i = parent->parent_[i];
+				return copy;
+			}
+
 			friend bool operator == (cycle_iterator const & i1, cycle_iterator const & i2)
 			{
 				return i1.i == i2.i;
 			}
+
+			friend bool operator != (cycle_iterator const & i1, cycle_iterator const & i2)
+			{
+				return i1.i != i2.i;
+			}
 		};
 
 		template <typename CycleCallback>