Fixed freezes on controller calling MarkPath() to invalid locations

AdventureMap.h

@@ -106,3 +106,63 @@ protected:
 	// Called when the game starts or when spawned
 	virtual void BeginPlay() override;
 };
+
+
+// only used for an experimental implementation of A*
+template <typename InElementType>
+struct TPriorityQueueNode {
+    InElementType Element;
+    float Priority;
+
+    TPriorityQueueNode()
+    {
+    }
+
+    TPriorityQueueNode(InElementType InElement, float InPriority)
+    {
+        Element = InElement;
+        Priority = InPriority;
+    }
+
+    bool operator<(const TPriorityQueueNode<InElementType> Other) const
+    {
+        return Priority < Other.Priority;
+    }
+};
+template <typename InElementType>
+class TPriorityQueue {
+public:
+    TPriorityQueue()
+    {
+        Array.Heapify();
+    }
+
+public:
+    // Always check if IsEmpty() before Pop-ing!
+    InElementType Pop()
+    {
+        TPriorityQueueNode<InElementType> Node;
+        Array.HeapPop(Node);
+        return Node.Element;
+    }
+
+    TPriorityQueueNode<InElementType> PopNode()
+    {
+        TPriorityQueueNode<InElementType> Node;
+        Array.HeapPop(Node);
+        return Node;
+    }
+
+    void Push(InElementType Element, float Priority)
+    {
+        Array.HeapPush(TPriorityQueueNode<InElementType>(Element, Priority));
+    }
+
+    bool IsEmpty() const
+    {
+        return Array.Num() == 0;
+    }
+
+public: // make private later on
+    TArray<TPriorityQueueNode<InElementType>> Array;
+};