no message

general/src/function/btree.cpp

@@ -1,5 +0,0 @@
-//
-// Created by 29019 on 2020/5/6.
-//
-
-#include "btree.h"

general/src/function/btree.h

@@ -1,14 +0,0 @@
-//
-// Created by 29019 on 2020/5/6.
-//
-
-#ifndef GENERAL_BTREE_H
-#define GENERAL_BTREE_H
-
-
-class btree {
-
-};
-
-
-#endif //GENERAL_BTREE_H

general/src/function/btree.hpp

@@ -0,0 +1,206 @@
+//
+// Created by 29019 on 2020/5/6.
+//
+
+#ifndef GENERAL_BTREE_H
+#define GENERAL_BTREE_H
+
+template<class K, int M = 3>
+struct BTreeNode
+{
+	K _keys[M];					// 关键字数组
+	BTreeNode<K, M>* _subs[M + 1];	// 孩子数组
+	size_t _size;				// 关键字的个数
+
+	BTreeNode<K, M>* _parent;	// 父亲
+
+	BTreeNode()
+		:_size(0)
+		, _parent(NULL)
+	{
+		for (size_t i = 0; i < M + 1; ++i)
+		{
+			_subs[i] = NULL;
+		}
+	}
+};
+
+template<class K, class V>
+struct Pair
+{
+	K _first;
+	V _second;
+
+	Pair(const K& k = K(), const V& v = V())
+		:_first(k)
+		, _second(v)
+	{}
+};
+
+template<class K, int M = 3>
+class BTree
+{
+	typedef BTreeNode<K, M> Node;
+public:
+	BTree()
+		:_root(NULL)
+	{}
+
+	Pair<Node*, int> Find(const K& key)
+	{
+		Node* parent = NULL;
+		Node* cur = _root;
+		while (cur)
+		{
+			int i = 0;
+			while (i < cur->_size && cur->_keys[i] < key)
+			{
+				++i;
+			}
+
+			if (cur->_keys[i] == key)
+			{
+				return Pair<Node*, int>(cur, i);
+			}
+
+			parent = cur;
+			cur = cur->_subs[i];
+		}
+
+		return Pair<Node*, int>(parent, -1);
+	}
+
+	bool Insert(const K& key)
+	{
+		if (_root == NULL)
+		{
+			_root = new Node;
+			_root->_keys[0] = key;
+			++_root->_size;
+
+			return true;
+		}
+
+		Pair<Node*, int> ret = Find(key);
+		if (ret._second != -1)
+		{
+			return false;
+		}
+
+		K k = key;
+		Node* cur = ret._first;
+		Node* sub = NULL;
+
+		// 在cur节点插入一个k
+		while (1)
+		{
+			_InsertKey(cur, k, sub);
+			if (cur->_size < M)
+			{
+				return true;
+			}
+
+			// 分裂
+			int boundary = M / 2;
+
+			Node* tmp = new Node;
+			size_t index = 0;
+			size_t size = cur->_size;
+
+			// 拷贝key
+			for (int i = boundary + 1; i < size; ++i)
+			{
+				tmp->_keys[index++] = cur->_keys[i];
+				tmp->_size++;
+				cur->_size--;
+			}
+			// 拷贝子节点
+			index = 0;
+			for (int i = boundary + 1; i <= size; ++i)
+			{
+				tmp->_subs[index] = cur->_subs[i];
+				if (tmp->_subs[index])
+					tmp->_subs[index]->_parent = tmp;
+
+				++index;
+			}
+
+			k = cur->_keys[boundary];
+			cur->_size--;
+
+			// 没有父亲
+			if (cur->_parent == NULL)
+			{
+				_root = new Node;
+				_root->_keys[0] = k;
+				_root->_subs[0] = cur;
+				_root->_subs[1] = tmp;
+				_root->_size = 1;
+
+				tmp->_parent = _root;
+				cur->_parent = _root;
+
+				return true;
+			}
+
+			cur = cur->_parent;
+			sub = tmp;
+		}
+	}
+
+	void _InsertKey(Node* cur, const K& k, Node* sub)
+	{
+		int i = cur->_size - 1;
+		while (i >= 0)
+		{
+			if (cur->_keys[i] > k)
+			{
+				cur->_keys[i + 1] = cur->_keys[i];
+				cur->_subs[i + 2] = cur->_subs[i + 1];
+
+				--i;
+			}
+			else
+			{
+				break;
+			}
+		}
+
+		cur->_keys[i + 1] = k;
+		cur->_subs[i + 2] = sub;
+		if (sub)
+		{
+			sub->_parent = cur;
+		}
+
+		cur->_size++;
+	}
+
+	void InOrder()
+	{
+		_InOrder(_root);
+		cout << endl;
+	}
+
+	void _InOrder(Node* root)
+	{
+		if (root == NULL)
+		{
+			return;
+		}
+
+		for (size_t i = 0; i < root->_size; ++i)
+		{
+			_InOrder(root->_subs[i]);
+			cout << root->_keys[i] << " ";
+		}
+
+		_InOrder(root->_subs[root->_size]);
+	}
+
+protected:
+	Node* _root;
+};
+
+
+#endif //GENERAL_BTREE_H