Add reset() function to cycle detector for safe reuse

Author: Marenz

libsolutil/Algorithms.h

@@ -68,6 +68,14 @@ class CycleDetector
 		return m_firstCycleVertex;
 	}
 
+	void reset()
+	{
+		m_processing.clear();
+		m_processed.clear();
+		m_depth = 0;
+		m_firstCycleVertex = nullptr;
+	}
+
 private:
 	Visitor m_visit;
 	std::set<V const*> m_processing;