4.set的模拟实现

首先我们要使用红黑树进行封装set即可，如下是RBTree.cpp的文件，有关红黑树的详细介绍，可以点击了解C++ 红黑树。

#include <iostream>
#include <vector>
using namespace std;
namespace rbtree
{enum Color{RED,BLACK,};//当我们需要存储键值对，那么T就是pair<K, V>//当我们只存储key值，那么T就是Ktemplate <class T>struct RBTreeNode{//构造函数RBTreeNode(T data):_left(nullptr), _right(nullptr), _parent(nullptr), _data(data), _col(RED){}//成员变量RBTreeNode* _left;RBTreeNode* _right;RBTreeNode* _parent;T _data;//节点数据Color _col;//颜色};//实现迭代器template<class T, class Ref, class Ptr>struct RBTreeIterator{typedef RBTreeNode<T> Node;typedef RBTreeIterator<T, Ref, Ptr> Self;Node* _node;//构造函数RBTreeIterator(Node* node):_node(node){}Ref operator*(){return _node->_data;}Ptr operator->(){return &(_node->_data);}bool operator==(const Self& s)const{return _node == s._node;}bool operator!=(const Self& s)const{return _node != s._node;}//前置++Self& operator++(){//如果右子树不为空，说明该树未取完，要取右子树的最左结点if (_node->_right){Node* left = _node->_right;while (left->_left){left = left->_left;}_node = left;}//右子树为空，说明该树已经取完，要回到cur为左孩子的parentelse{Node* cur = _node, * parent = cur->_parent;while (parent && parent->_right == cur){cur = parent;parent = cur->_parent;}_node = parent;}return *this;}//后置++Self operator++(int){Self old = new Self(_node);//如果右子树不为空，说明该树未取完，要取右子树的最左结点if (_node->_right){Node* left = _node->_right;while (left->_left){left = left->_left;}_node = left;}//右子树为空，说明该树已经取完，要回到cur为左孩子的parentelse{Node* cur = _node, * parent = cur->_parent;while (parent && parent->_right == cur){cur = parent;parent = cur->_parent;}_node = parent;}return old;}//前置--Self& operator--(){Self old = new Self(_node);//如果左子树不为空，说明该树未取完，要取左子树的最右结点if (_node->_left){Node* right = _node->_left;while (right->_right){right = right->_right;}_node = right;}//左子树为空，说明该树已经取完，要回到cur为右孩子的parentelse{Node* cur = _node, * parent = cur->_parent;while (parent && parent->_left == cur){cur = parent;parent = cur->_parent;}_node = parent;}return old;}//后置--Self operator--(int){//如果左子树不为空，说明该树未取完，要取左子树的最右结点if (_node->_left){Node* right = _node->_left;while (right->_right){right = right->_right;}_node = right;}//左子树为空，说明该树已经取完，要回到cur为右孩子的parentelse{Node* cur = _node, * parent = cur->_parent;while (parent && parent->_left == cur){cur = parent;parent = cur->_parent;}_node = parent;}return *this;}};//前面的K用于传入key的类型，后面的T用于传入红黑树存储的数据类型。keyOfT仿函数，取出T对象中的key,用于比较template<class K, class T, class KeyOfT>class RBTree{typedef typename RBTreeNode<T> Node;typedef typename RBTreeIterator<T, T&, T*> iterator;public://构造函数RBTree():_root(nullptr){} //析构函数~RBTree(){Destroy(_root);_root = nullptr;}iterator begin(){Node* left = _root;while (left->_left){left = left->_left;}return iterator(left);}iterator end(){return iterator(nullptr);}pair<iterator, bool> Insert(const T& data){KeyOfT kot; if (_root == nullptr){_root = new Node(data);_root->_col = BLACK;return make_pair(iterator(_root), true);}//找位置插入Node* cur = _root, * parent = _root;while (cur){if (kot(data) < kot(cur->_data)){parent = cur;cur = cur->_left;}else if (kot(data) > kot(cur->_data)){parent = cur;cur = cur->_right;}else{return make_pair(iterator(cur), false);}}cur = new Node(data);cur->_parent = parent;if (kot(data) < kot(parent->_data)){parent->_left = cur;}else{parent->_right = cur;}Node* ret = cur;//检查颜色(当连续出现两个红色时需要调整)while (parent && parent->_col == RED){Node* grandparent = parent->_parent;if (parent == grandparent->_left){Node* uncle = grandparent->_right;//如果uncle存在且为红，则将parent和uncle变黑，grandparent变红if (uncle && uncle->_col == RED){parent->_col = uncle->_col = BLACK;grandparent->_col = RED;//继续向上检查cur = grandparent;parent = cur->_parent;}//uncle不存在或者为黑else{//将grandparent右旋，grandparent变为红,parent变为黑if (cur == parent->_left){RotateR(grandparent);grandparent->_col = RED;parent->_col = BLACK;}//将parent左旋，grandparent右旋，将cur变为黑，grandparent变为红else{RotateL(parent);RotateR(grandparent);grandparent->_col =  RED;cur->_col = BLACK;}//此时最上面的结点为黑，可以直接结束break;}}else{Node* uncle = grandparent->_left;//如果uncle存在且为红，则将parent和uncle变黑，grandparent变红if (uncle && uncle->_col == RED){parent->_col = uncle->_col = BLACK;grandparent->_col = RED;//继续向上检查cur = grandparent;parent = cur->_parent;}//uncle不存在或者为黑else{//将grandparent左旋，grandparent变为红,parent变为黑if (cur == parent->_right){RotateL(grandparent);grandparent->_col = RED;parent->_col = BLACK;}//将parent右旋，grandparent左旋，将cur变为黑，grandparent变为红else{RotateR(parent);RotateL(grandparent);grandparent->_col = RED;cur->_col = BLACK;}break;}}}//把根节点变为黑_root->_col = BLACK;return make_pair(iterator(ret), true);}bool _IsRBTree(Node* root, int count, int blacknum){if (root == nullptr){if (count != blacknum){return false;}return true;}if (root->_col == BLACK){count++;}return _IsRBTree(root->_left, count, blacknum) &&_IsRBTree(root->_right, count, blacknum);}bool IsRBTree(){if (_root->_col == RED){return false;}int blacknum = 0;Node* cur = _root;while (cur){if (cur->_col == BLACK){blacknum++;}cur = cur->_left;}return _IsRBTree(_root, 0, blacknum);}void _InOrder(Node* root){KeyOfT kot;if (root == nullptr){return;}_InOrder(root->_left);cout << kot(root->_data) << " ";_InOrder(root->_right);}void InOrder(){_InOrder(_root);cout << endl;}private:void Destroy(Node* root){if (root == nullptr){return;}Destroy(root->_left);Destroy(root->_right);delete root;}//左单旋void RotateL(Node* parent){Node* subR = parent->_right;Node* subRL = subR->_left;Node* grandparent = parent->_parent;parent->_right = subRL;if (subRL){subRL->_parent = parent;}subR->_left = parent;parent->_parent = subR;if (parent == _root){_root = subR;}else{if (grandparent->_left == parent)grandparent->_left = subR;elsegrandparent->_right = subR;}subR->_parent = grandparent;}//右单旋void RotateR(Node* parent){Node* subL = parent->_left;Node* subLR = subL->_right;Node* grandparent = parent->_parent;parent->_left = subLR;if (subLR){subLR->_parent = parent;}subL->_right = parent;parent->_parent = subL;if (parent == _root){_root = subL;}else{if (grandparent->_left == parent)grandparent->_left = subL;elsegrandparent->_right = subL;}subL->_parent = grandparent;}//左右双旋void RotateLR(Node* parent){Node* subL = parent->_left;Node* subLR = subL->_right;int bf = subLR->_bf;RotateL(subL);RotateR(parent);}//右左双旋void RotateRL(Node* parent){Node* subR = parent->_right;Node* subRL = parent->_left;int bf = subRL->_bf;RotateR(subR);RotateL(parent);}Node* _root;};
};

set.cpp文件如下

#include "RBTree.cpp"
namespace lbk
{template<class K>class set{struct SetKeyOfT{const K& operator()(const K& key){return key;}};public:typedef typename rbtree::RBTreeIterator<K, K&, K*> iterator;iterator begin(){return _t.begin();}iterator end(){return _t.end();}pair<iterator, bool> insert(const K& key){return _t.Insert(key);}void InOrder(){_t.InOrder();}private://前面的K用于传入key的类型，后面的T用于传入红黑树存储的数据类型。//红黑树中存储的值不可以改变，应加上constrbtree::RBTree<K, const K, SetKeyOfT> _t;};
};