fixup commit

src/tree/binarytree.hpp

@@ -11,9 +11,14 @@ struct Node
 	std::unique_ptr<Node<T>> left;
 	std::unique_ptr<Node<T>> right;
 
+	bool HasChildren() const
+	{
+		return static_cast<bool>(left) || static_cast<bool>(right);
+	}
+
 	bool IsLeaf() const
 	{
-		return left == nullptr && right == nullptr;
+		return !HasChildren();
 	}
 
 	Node(T const &_value)
@@ -30,40 +35,52 @@ class Tree
 private:
 	std::unique_ptr<Node<T>> root;
 
-	std::unique_ptr<Node<T>> & GetRightMostLeaf(std::unique_ptr<Node<T>> &node)
+	T ExtractSmallestLeaf(std::unique_ptr<Node<T>> &node)
 	{
-		std::unique_ptr<Node<T>> *nodePtr = &node;
-		while ((*nodePtr)->right != nullptr)
+		std::unique_ptr<Node<T>> *nodePtr = &(node);
+		while ((*nodePtr)->HasChildren())
 		{
-			nodePtr = &((*nodePtr)->right);
+			if((*nodePtr)->left)
+			{
+				nodePtr = &((*nodePtr)->left);
+			}
+			else
+			{
+				T value = (*nodePtr)->value;
+				(*nodePtr) = std::move((*nodePtr)->right);
+				return value;
+			}
 		} 
 
-		return *nodePtr;
+		T value = (*nodePtr)->value;
+		(*nodePtr).release();
+		return value;
 	}
 
 	void DeleteNode(std::unique_ptr<Node<T>> & node)
 	{
-		if(node || node->IsLeaf())
+		if(!node || node->IsLeaf())
 		{
 			node.release();
+			return;
 		}
 
-		if(node->left)
+		if(!(node->left))
 		{
 			node = std::move(node->right);
+			return;
 		}
 
-		if(node->right)
+		if(!(node->right))
 		{
 			node = std::move(node->left);
+			return;
 		}
 
-		auto & replacementNode = GetRightMostLeaf(node);
-		replacementNode->left.swap(node->left);
-		replacementNode->right.swap(node->right);
-		node.swap(replacementNode);
+		// In order successor
 
-		replacementNode.release();
+		auto newNodeValue = ExtractSmallestLeaf(node->right);
+		node->value = newNodeValue;
 	}
 
 	std::unique_ptr<Node<T>> & FindNode(T const & value)
@@ -80,7 +97,6 @@ private:
 				currentPtr = &((*currentPtr)->right);
 			}
 		}
-
 		return *currentPtr;
 	}
 
@@ -121,10 +137,6 @@ public:
 	void Delete(T const & value)
 	{
 		auto & node = FindNode(value);
-		if (node)
-		{
-			return;
-		}
 		DeleteNode(node);
 	}