目录
底层对比:
底层红黑树结构和set、map:
底层模拟:
传值调用:
迭代器:
operator ++()
find函数
operator() 、仿函数
set和map的仿函数 :
图解:
insert函数:
构造函数,析构函数:
析构函数:
拷贝构造函数:
赋值函数:
map的封装:
set的封装:
红黑树的修改:
底层对比:
上图以kv模型为例
通过底层可以看出:
- set和map的底层调用都是调用了红黑树 rb_tree
- set和map在底层最大的区别就是value的不同,set的value仍然是key类型的,但是map的value是pair<const key,T>类型的
- 也因为类型的不同,二者使用的template 类模板也相差了一个class T ,而这个class T表示的其实就是map的value中的second的数值类型
- 同时因为value的不同,所以导致了map和set在红黑树中存储的数据也并不相同
底层红黑树结构和set、map:
底层模拟:
传值调用:
迭代器:
- 不论是set还是map 的迭代器,关键得是看红黑树的迭代器
- 树的内部迭代器其实就是和链表相差不多,需要进行一个内部的重载调用
- 也就是说 operator-> operator * operator ++ operator --都是需要进行内部重载,然后进行封装的!
RBTree.htemplate<class T, class Ref, class Ptr>
struct __RBTreeIterator
{typedef RBTreeNode<T> Node;typedef __RBTreeIterator<T, Ref, Ptr> Self;Node* _node;__RBTreeIterator(Node* node):_node(node){}Ref operator*(){return _node->_data;}Ptr operator->(){return &_node->_data;}bool operator!=(const Self& s){return _node != s._node;}Self& operator++(){if (_node->_right){// 下一个,右树最左节点Node* leftMin = _node->_right;while (leftMin->_left){leftMin = leftMin->_left;}_node = leftMin;}else{// 下一个,孩子等于父亲左的那个祖先Node* cur = _node;Node* parent = cur->_parent;while (parent && cur == parent->_right){cur = parent;parent = parent->_parent;}_node = parent;}return *this;}
};
operator ++()
是实现迭代器的难点之一,因为红黑树的本质其实是二叉搜索树,所以遍历是使用中序遍历,所以++和--都是使用 中序遍历的节点,如下图所示,it所在位置的下一个节点是15
首先我们需要知道,中序遍历的过程是 左子树 根节点 右子树 所以可以通过下图右可以得出:
- 当前it所在的位置是它父亲节点的左节点,那么下一个需要遍历的节点就是it的父亲节点
- 当前节点的右子树是空的,那么表示这个节点的右子树结束遍历,下一个需要遍历和++递达的节点,应该往上进行查找祖先节点
- 如果当前节点的右子树是空的,且当前节点是其父亲节点的右节点,那么表示要去父亲节点更往上的方向寻找下一个需要遍历的节点
- 如果当前节点的右子树是空的/遍历完了,且当前节点是其父亲节点的左节点,那么表示当前节点结束,返回父亲节点且下一个访问的节点就是父亲节点,且同时访问完后需要取父亲节点的右子树中进行遍历和寻找下一个++位置的节点
- 最后一个单独的处理,那就是走到最后一个节点的时候,走到最后一个节点的右子树是空的,就一直返回到根节点,这时候就需要给迭代器置空了!
- ++的下一个节点是该节点右子树中的最左节点!
- leftMin = node->right 表示进入右子树中寻找最左节点,当然现在的条件是右子树存在,如果右子树存在就是上面,如果不存在就需要往上边寻找,直到找到某个节点是它父亲节点的左节点为止,或者说找到的某个节点,他没有父亲节点它是根节点为止!
- 要求当前的节点是他父亲节点的右节点,如果一直是这样就需要一直往上走,直到当前节点是它父亲节点的左节点时,返回父亲节点
- 且需要注意如果当前节点是根节点,那么它的父亲就是空的,空的不能再继续往上寻找了,所以直接跳出循环,最后返回父亲节点!
RBTree.h
//红黑树中调动迭代器的函数方法
typedef __RBTreeIterator<T, T&, T*> Iterator;
typedef __RBTreeIterator<T, const T&, const T*> ConstIterator;Iterator Begin(){Node* leftMin = _root;while (leftMin && leftMin->_left){leftMin = leftMin->_left;}return Iterator(leftMin);}Iterator End(){return Iterator(nullptr);}ConstIterator End() const{return ConstIterator(nullptr);}ConstIterator Begin() const{Node* leftMin = _root;while (leftMin && leftMin->_left){leftMin = leftMin->_left;}return ConstIterator(leftMin);}
find函数
RBTree.hIterator Find(const K& key){Node* cur = _root;while (cur){if (cur->_key < key){cur = cur->_right;}else if (cur->_key > key){cur = cur->_left;}else{return Iterator(cur);}}return End();}
operator() 、仿函数
使用仿函数的原因其实是在insert函数中需要使用operator()的原因,因为在insert函数中,需要使用比较大小之间的问题,而为了让红黑树同时适应set和map(主要是针对map的pair内部问题),需要对取值之间进行正确取值的操作。
如上图所示,在set中data可以直接对于set中的value,但是对于map来说,需要在pair中进行取值,所以map需要一个详细的对应关系,这就造成了仿函数Key0fT的诞生
RBTree.h//树的最终的基础结构
template<class K, class T, class KeyOfT>
class RBTree
{typedef RBTreeNode<T> Node;public:typedef __RBTreeIterator<T, T&, T*> Iterator;typedef __RBTreeIterator<T, const T&, const T*> ConstIterator;
private:Node* _root = nullptr;
};
set和map的仿函数 :
//Myset.hstruct SetKeyOfT{const K& operator()(const K& key){return key;}};//Mymap.hstruct MapKeyOfT{const K& operator()(const pair<K, V>& kv){return kv.first;}};
图解:
insert函数:
pair<Iterator, bool> Insert(const T& data){if (_root == nullptr){_root = new Node(data);_root->_col = BLACK;return make_pair(Iterator(_root), true);}KeyOfT kot;//调用了仿函数,方便之后的比较Node* parent = nullptr;Node* cur = _root;while (cur){// K// pair<K, V>// kot对象,是用来取T类型的data对象中的keyif (kot(cur->_data) < kot(data)){parent = cur;cur = cur->_right;}else if (kot(cur->_data) > kot(data)){parent = cur;cur = cur->_left;}else{return make_pair(Iterator(cur), false);}}cur = new Node(data);Node* newnode = cur;cur->_col = RED; // 新增节点给红色if (kot(parent->_data) < kot(data)){parent->_right = cur;}else{parent->_left = cur;}cur->_parent = parent;// parent的颜色是黑色也结束while (parent && parent->_col == RED){// 关键看叔叔Node* grandfather = parent->_parent;if (parent == grandfather->_left){Node* uncle = grandfather->_right;// 叔叔存在且为红,-》变色即可if (uncle && uncle->_col == RED){parent->_col = uncle->_col = BLACK;grandfather->_col = RED;// 继续往上处理cur = grandfather;parent = cur->_parent;}else // 叔叔不存在,或者存在且为黑{if (cur == parent->_left){// g // p u// c RotateR(grandfather);parent->_col = BLACK;grandfather->_col = RED;}else{// g // p u// c RotateL(parent);RotateR(grandfather);cur->_col = BLACK;grandfather->_col = RED;}break;}}else{Node* uncle = grandfather->_left;// 叔叔存在且为红,-》变色即可if (uncle && uncle->_col == RED){parent->_col = uncle->_col = BLACK;grandfather->_col = RED;// 继续往上处理cur = grandfather;parent = cur->_parent;}else // 叔叔不存在,或者存在且为黑{// 情况二:叔叔不存在或者存在且为黑// 旋转+变色// g// u p// cif (cur == parent->_right){RotateL(grandfather);parent->_col = BLACK;grandfather->_col = RED;}else{// g// u p// cRotateR(parent);RotateL(grandfather);cur->_col = BLACK;grandfather->_col = RED;}break;}}}_root->_col = BLACK;return make_pair(Iterator(newnode), true);}
构造函数,析构函数:
析构函数:
~RBTree(){Destroy(_root);_root = nullptr;}private:void Destroy(Node* root){if (root == nullptr)return;Destroy(root->_left);Destroy(root->_right);delete root;root = nullptr;}
拷贝构造函数:
拷贝构造函数使用的是前序遍历,且内部需要三条链接的拷贝和构造,也就是左子树、右子树、和父亲节点,同时也需要进行节点颜色的拷贝操作,所以拷贝构造的内部其实是一个前序遍历+颜色的拷贝+左右子树的拷贝和链接+递归遍历
RBTree(const RBTree<K, T, KeyOfT>& t){_root = Copy(t._root);}private:Node* Copy(Node* root){//因为要有父亲节点的链接,所以需要一个反向链接//其次也需要进行颜色的拷贝!因为是红黑树!if (root == nullptr)return nullptr;Node* newroot = new Node(root->_data);newroot->_col = root->_col;newroot->_left = Copy(root->_left);if (newroot->_left)newroot->_left->_parent = newroot;newroot->_right = Copy(root->_right);if (newroot->_right)newroot->_right->_parent = newroot;return newroot;}
赋值函数:
//RBTree.hRBTree<K, T, KeyOfT>& operator=(RBTree<K, T, KeyOfT> t){swap(_root, t._root);return *this;}
map的封装:
namespace bit
{template<class K, class V>class map{struct MapKeyOfT{const K& operator()(const pair<K, V>& kv){return kv.first;}};public:typedef typename RBTree<K, pair<const K, V>, MapKeyOfT>::Iterator iterator;typedef typename RBTree<K, const K, MapKeyOfT>::ConstIterator const_iterator;const_iterator begin() const{return _t.Begin();}const_iterator end() const{return _t.End();}iterator begin() {return _t.Begin();}iterator end() {return _t.End();}iterator find(const K& key){return _t.Find(key);}pair<iterator, bool> insert(const pair<K, V>& kv){return _t.Insert(kv);}V& operator[](const K& key){pair<iterator, bool> ret = _t.Insert(make_pair(key, V()));return ret.first->second;}private:RBTree<K, pair<const K, V>, MapKeyOfT> _t;};
set的封装:
namespace bit
{template<class K>class set{struct SetKeyOfT{const K& operator()(const K& key){return key;}};public:typedef typename RBTree<K, const K, SetKeyOfT>::Iterator iterator;typedef typename RBTree<K, const K, SetKeyOfT>::ConstIterator const_iterator;const_iterator begin() const{return _t.Begin();}const_iterator end() const{return _t.End();}iterator begin(){return _t.Begin();}iterator end(){return _t.End();}iterator find(const K& key){return _t.Find(key);}pair<iterator, bool> insert(const K& key){return _t.Insert(key);}private:RBTree<K, const K, SetKeyOfT> _t;};void PrintSet(const set<int>& s){for (auto e : s){cout << e << endl;}}
红黑树的修改:
#pragma once
#include<vector>enum Colour
{RED,BLACK
};template<class T>
struct RBTreeNode
{RBTreeNode<T>* _left;RBTreeNode<T>* _right;RBTreeNode<T>* _parent;T _data;Colour _col;RBTreeNode(const T& data):_left(nullptr), _right(nullptr), _parent(nullptr), _data(data), _col(RED){}
};template<class T, class Ref, class Ptr>
struct __RBTreeIterator
{typedef RBTreeNode<T> Node;typedef __RBTreeIterator<T, Ref, Ptr> Self;Node* _node;__RBTreeIterator(Node* node):_node(node){}Ref operator*(){return _node->_data;}Ptr operator->(){return &_node->_data;}bool operator!=(const Self& s){return _node != s._node;}Self& operator++(){if (_node->_right){// 下一个,右树最左节点Node* leftMin = _node->_right;while (leftMin->_left){leftMin = leftMin->_left;}_node = leftMin;}else{// 下一个,孩子等于父亲左的那个祖先Node* cur = _node;Node* parent = cur->_parent;while (parent && cur == parent->_right){cur = parent;parent = parent->_parent;}_node = parent;}return *this;}
};template<class K, class T, class KeyOfT>
class RBTree
{typedef RBTreeNode<T> Node;public:typedef __RBTreeIterator<T, T&, T*> Iterator;typedef __RBTreeIterator<T, const T&, const T*> ConstIterator;RBTree() = default;RBTree(const RBTree<K, T, KeyOfT>& t){_root = Copy(t._root);}// t2 = t1RBTree<K, T, KeyOfT>& operator=(RBTree<K, T, KeyOfT> t){swap(_root, t._root);return *this;}~RBTree(){Destroy(_root);_root = nullptr;}Iterator Begin(){Node* leftMin = _root;while (leftMin && leftMin->_left){leftMin = leftMin->_left;}return Iterator(leftMin);}Iterator End(){return Iterator(nullptr);}ConstIterator End() const{return ConstIterator(nullptr);}ConstIterator Begin() const{Node* leftMin = _root;while (leftMin && leftMin->_left){leftMin = leftMin->_left;}return ConstIterator(leftMin);}Iterator Find(const K& key){Node* cur = _root;while (cur){if (cur->_key < key){cur = cur->_right;}else if (cur->_key > key){cur = cur->_left;}else{return Iterator(cur);}}return End();}// 20:10pair<Iterator, bool> Insert(const T& data){if (_root == nullptr){_root = new Node(data);_root->_col = BLACK;return make_pair(Iterator(_root), true);}KeyOfT kot;Node* parent = nullptr;Node* cur = _root;while (cur){// K// pair<K, V>// kot对象,是用来取T类型的data对象中的keyif (kot(cur->_data) < kot(data)){parent = cur;cur = cur->_right;}else if (kot(cur->_data) > kot(data)){parent = cur;cur = cur->_left;}else{return make_pair(Iterator(cur), false);}}cur = new Node(data);Node* newnode = cur;cur->_col = RED; // 新增节点给红色if (kot(parent->_data) < kot(data)){parent->_right = cur;}else{parent->_left = cur;}cur->_parent = parent;// parent的颜色是黑色也结束while (parent && parent->_col == RED){// 关键看叔叔Node* grandfather = parent->_parent;if (parent == grandfather->_left){Node* uncle = grandfather->_right;// 叔叔存在且为红,-》变色即可if (uncle && uncle->_col == RED){parent->_col = uncle->_col = BLACK;grandfather->_col = RED;// 继续往上处理cur = grandfather;parent = cur->_parent;}else // 叔叔不存在,或者存在且为黑{if (cur == parent->_left){// g // p u// c RotateR(grandfather);parent->_col = BLACK;grandfather->_col = RED;}else{// g // p u// c RotateL(parent);RotateR(grandfather);cur->_col = BLACK;grandfather->_col = RED;}break;}}else{Node* uncle = grandfather->_left;// 叔叔存在且为红,-》变色即可if (uncle && uncle->_col == RED){parent->_col = uncle->_col = BLACK;grandfather->_col = RED;// 继续往上处理cur = grandfather;parent = cur->_parent;}else // 叔叔不存在,或者存在且为黑{// 情况二:叔叔不存在或者存在且为黑// 旋转+变色// g// u p// cif (cur == parent->_right){RotateL(grandfather);parent->_col = BLACK;grandfather->_col = RED;}else{// g// u p// cRotateR(parent);RotateL(grandfather);cur->_col = BLACK;grandfather->_col = RED;}break;}}}_root->_col = BLACK;return make_pair(Iterator(newnode), true);}void RotateR(Node* parent){Node* subL = parent->_left;Node* subLR = subL->_right;parent->_left = subLR;if (subLR)subLR->_parent = parent;subL->_right = parent;Node* ppNode = parent->_parent;parent->_parent = subL;if (parent == _root){_root = subL;_root->_parent = nullptr;}else{if (ppNode->_left == parent){ppNode->_left = subL;}else{ppNode->_right = subL;}subL->_parent = ppNode;}}void RotateL(Node* parent){Node* subR = parent->_right;Node* subRL = subR->_left;parent->_right = subRL;if (subRL)subRL->_parent = parent;subR->_left = parent;Node* ppNode = parent->_parent;parent->_parent = subR;if (parent == _root){_root = subR;_root->_parent = nullptr;}else{if (ppNode->_right == parent){ppNode->_right = subR;}else{ppNode->_left = subR;}subR->_parent = ppNode;}}void InOrder(){_InOrder(_root);cout << endl;}bool IsBalance(){if (_root->_col == RED){return false;}int refNum = 0;Node* cur = _root;while (cur){if (cur->_col == BLACK){++refNum;}cur = cur->_left;}return Check(_root, 0, refNum);}private:Node* Copy(Node* root){if (root == nullptr)return nullptr;Node* newroot = new Node(root->_data);newroot->_col = root->_col;newroot->_left = Copy(root->_left);if (newroot->_left)newroot->_left->_parent = newroot;newroot->_right = Copy(root->_right);if (newroot->_right)newroot->_right->_parent = newroot;return newroot;}void Destroy(Node* root){if (root == nullptr)return;Destroy(root->_left);Destroy(root->_right);delete root;root = nullptr;}bool Check(Node* root, int blackNum, const int refNum){if (root == nullptr){//cout << blackNum << endl;if (refNum != blackNum){cout << "存在黑色节点的数量不相等的路径" << endl;return false;}return true;}if (root->_col == RED && root->_parent->_col == RED){//cout << root->_kv.first << "存在连续的红色节点" << endl;return false;}if (root->_col == BLACK){blackNum++;}return Check(root->_left, blackNum, refNum)&& Check(root->_right, blackNum, refNum);}void _InOrder(Node* root){if (root == nullptr){return;}_InOrder(root->_left);cout << root->_kv.first << ":" << root->_kv.second << endl;_InOrder(root->_right);}private:Node* _root = nullptr;//size_t _size = 0;
};