From 554c94aa5b1b1161109c91a0764b7197e0e38908 Mon Sep 17 00:00:00 2001
From: Tijmen van Nesselrooij <tijmen_222@hotmail.com>
Date: Sun, 28 Apr 2019 16:09:36 +0200
Subject: [PATCH] Binary tree impl

---
 binary-trees/binarytree.hpp | 180 +++++++++++++++++++++++-------------
 1 file changed, 118 insertions(+), 62 deletions(-)

diff --git a/binary-trees/binarytree.hpp b/binary-trees/binarytree.hpp
index 5f6e8ad..ea09ff4 100644
--- a/binary-trees/binarytree.hpp
+++ b/binary-trees/binarytree.hpp
@@ -2,74 +2,130 @@
 
 namespace BinaryTree
 {
-    template<class T>
-    struct Node
-    {
-        Node * parent;
+template <class T>
+struct Node
+{
+	Node *parent;
 
-        T value;
+	T value;
 
-        std::unique_ptr<Node<T>> left;
-        std::unique_ptr<Node<T>> right;
+	std::unique_ptr<Node<T>> left;
+	std::unique_ptr<Node<T>> right;
 
-        Node(T const & _value, Node<T> * _parent)
-            : parent(_parent),
-            value(_value)
-        {}
-    };
+	bool IsLeaf() const
+	{
+		return left == nullptr && right == nullptr;
+	}
 
-    template<class T>
-    class Tree
-    {
-    private:
-        std::unique_ptr<Node<T>> root;
+	Node(T const &_value, Node<T> *_parent)
+			: parent(_parent),
+				value(_value)
+	{
+	}
+};
 
-    public:
-        void Insert(T & value)
-        {
-            Node<T> * previousPtr = nullptr;
-            std::unique_ptr<Node<T>> & ptr = root;
-            while(ptr != nullptr)
-            {
-                previousPtr = ptr.get();
-                if(ptr->value > value)
-                {
-                    ptr = ptr->left;
-                }
-                else
-                {
-                    ptr = ptr->right;
-                }        
-            }
-            ptr = std::make_unique<Node<T>>(value, previousPtr);
-        }
+template <class T>
+class Tree
+{
+private:
+	std::unique_ptr<Node<T>> root;
 
-        bool Contains(T const & value)
-        {
-            std::unique_ptr<Node<T>> & ptr = root;
-            while(ptr != nullptr)
-            {
-                if(ptr->value == value)
-                {
-                    return true;
-                }
+	std::unique_ptr<Node<T>> & GetRightMostLeaf(std::unique_ptr<Node<T>> &localRoot)
+	{
+		std::unique_ptr<Node<T>> *nodePtr = &localRoot;
+		while ((*nodePtr)->right != nullptr)
+		{
+			nodePtr = &((*nodePtr)->right);
+		}
 
-                if(ptr->value > value)
-                {
-                    ptr = ptr->left;
-                }
-                else
-                {
-                    ptr = ptr->right;
-                }        
-            }
+		return *nodePtr;
+	}
 
-            return false;
-        }
+public:
+	void Insert(T value)
+	{
+		Node<T> *previousPtr = nullptr;
+		std::unique_ptr<Node<T>> *rootPtr = &root;
+		while (*rootPtr != nullptr)
+		{
+			previousPtr = rootPtr->get();
+			if ((*rootPtr)->value > value)
+			{
+				rootPtr = &((*rootPtr)->left);
+			}
+			else
+			{
+				rootPtr = &((*rootPtr)->right);
+			}
+		}
+		*rootPtr = std::make_unique<Node<T>>(value, previousPtr);
+	}
 
-        void Delete(T const & value)
-        {
-            
-        }
-    };
-}
\ No newline at end of file
+	bool Contains(T const value)
+	{
+		std::unique_ptr<Node<T>> *rootPtr = &root;
+		while (*rootPtr != nullptr)
+		{
+			if ((*rootPtr)->value == value)
+			{
+				return true;
+			}
+
+			if ((*rootPtr)->value > value)
+			{
+				rootPtr = &((*rootPtr)->left);
+			}
+			else
+			{
+				rootPtr = &((*rootPtr)->right);
+			}
+		}
+
+		return false;
+	}
+
+	void Delete(T const value)
+	{
+		std::unique_ptr<Node<T>> *rootPtr = &root;
+		while (*rootPtr != nullptr)
+		{
+			if ((*rootPtr)->value == value)
+			{
+				if ((*rootPtr)->IsLeaf())
+				{
+					rootPtr->release();
+					return;
+				}
+
+				if ((*rootPtr)->left == nullptr)
+				{
+					rootPtr->swap((*rootPtr)->right);
+					(*rootPtr)->right.release();
+				}
+				else if ((*rootPtr)->right == nullptr)
+				{
+					rootPtr->swap((*rootPtr)->left);
+					(*rootPtr)->left.release();
+				}
+				else
+				{
+					auto &replacementNode = GetRightMostLeaf((*rootPtr)->left);
+					rootPtr->swap(replacementNode);
+					replacementNode.release();
+				}
+
+				return;
+			}
+
+			if ((*rootPtr)->value > value)
+			{
+				rootPtr = &((*rootPtr)->left);
+			}
+			else
+			{
+				rootPtr = &((*rootPtr)->right);
+			}
+		}
+	}
+};
+} // namespace BinaryTree
\ No newline at end of file