用红黑树实现map和set
上一篇文章讲解了如何实现红黑树:
https://blog.csdn.net/Radium_1209/article/details/104873813
这里我们用已经实现的红黑树来写一个简单的map和set。
因为map有两个参数,所以我们要先对原来的代码进行微调,将传入的参数调整为Key和Value。
还有一些地方需要微调,详见https://github.com/Radium1209/Red-Black-Tree
红黑树的接口定义
#ifndef RED_BLACK_TREE
#define RED_BALCK_TREE
#include <stdlib.h>
/* 红黑树颜色 */
enum RBTColor
{
RED,
BLACK,
};
/* 红黑树节点 */
template<class Key, class Value>
class RBTNode
{
public:
RBTNode( RBTColor col, Key k, Value val, RBTNode* lch, RBTNode* rch, RBTNode* fa )
: color( col ), key( k ), value( val ), blackNum( 0 ), leftChild( lch ), rightChild( rch ), father( fa ) {}
RBTColor color; // 颜色(红或黑)
Key key; // 关键字
Value value; // 数据
int blackNum; // 该节点的路径包含的黑色节点个数
RBTNode *leftChild; // 左孩子
RBTNode *rightChild; // 右孩子
RBTNode *father; // 父节点
};
/* 节点-层数对,用于遍历 */
template<class Key, class Value>
class NLPair
{
public:
NLPair( RBTNode<Key, Value>* node, int layer )
: node( node ), layer( layer ) {}
RBTNode<Key, Value>* node;
unsigned int layer;
};
template<class Key, class Value>
class RBTree
{
private:
RBTNode<Key, Value> *root;
public:
RBTree();
~RBTree();
// 判断是否为红黑树
bool isRBT();
// 各种插入函数
void insert( Key key );
void insert( Key key, Value value );
void insertUnique( Key key );
void insertUnique( Key key, Value value );
// 删除函数
void erase( Key key );
// 清空
void clear();
// 查询函数
RBTNode<Key, Value>* find( Key key );
// 画红黑树,测试用
void draw();
// 求开始结束节点,此处没有实现iterator,所以用处不大
RBTNode<Key, Value>* begin();
RBTNode<Key, Value>* end();
// 求节点个数和是否为空
unsigned int size();
bool empty();
// 一些内部函数
private:
bool isBST( RBTNode<Key, Value> *node );
bool hasTwoRed( RBTNode<Key, Value> *node );
bool hasSameBlack( RBTNode<Key, Value> *node );
void calBlackNum( RBTNode<Key, Value> *node, int blackNum );
void leftRotate( RBTNode<Key, Value> *root );
void rightRotate( RBTNode<Key, Value> *root );
void insert( RBTNode<Key, Value> *node );
void insertFix( RBTNode<Key, Value> *node );
void erase( RBTNode<Key, Value> *node );
void eraseFix( RBTNode<Key, Value> *node );
void eraseNode( RBTNode<Key, Value> *node );
void clear( RBTNode<Key, Value> *node );
RBTNode<Key, Value>* find( RBTNode<Key, Value> *node, Key key );
unsigned int size( RBTNode<Key, Value> *node );
};
#include "rbTree.cpp"
#endif
set
set完全直接调用红黑树的接口即可,不用进行任何修改。我们只实现了简单的插入删除查询等函数。因为set是没有重复元素的,我们可以模仿STL实现两个insert函数,一个可以插入重复的key,另一个只能插入不重复的节点。
// mySet.h
#ifndef MY_SET
#define MY_SET
template<class Key>
class mySet
{
private:
RBTree<Key, Key>* rbt;
public:
mySet();
~mySet();
public:
RBTNode<Key, Key>* begin();
RBTNode<Key, Key>* end();
void clear();
void insert( Key key );
void erase( Key key );
unsigned int size();
RBTNode<Key, Key>* find( Key key );
bool empty();
};
#include "mySet.cpp"
#endif
template<class Key>
mySet<Key>::mySet()
{
rbt = new RBTree<Key, Key>();
}
template<class Key>
mySet<Key>::~mySet()
{
delete rbt;
}
template<class Key>
RBTNode<Key, Key>* mySet<Key>::begin()
{
return rbt->begin();
}
template<class Key>
RBTNode<Key, Key>* mySet<Key>::end()
{
return rbt->end();
}
template<class Key>
void mySet<Key>::clear()
{
rbt->clear();
}
template<class Key>
void mySet<Key>::insert( Key key )
{
rbt->insertUnique( key );
}
template<class Key>
void mySet<Key>::erase( Key key )
{
rbt->erase( key );
}
template<class Key>
unsigned int mySet<Key>::size()
{
return rbt->size();
}
template<class Key>
RBTNode<Key, Key>* mySet<Key>::find( Key key )
{
return rbt->find( key );
}
template<class Key>
bool mySet<Key>::empty()
{
return rbt->empty();
}
map
map的话也基本上差不多,也是直接用红黑树就可以。这边重载了一下[],使其可以直接赋值。修改了一下之前的insert函数,使其返回一个指针。
// myMap.h
#ifndef MY_MAP
#define MY_MAP
template<class Key, class Value>
class myMap
{
private:
RBTree<Key, Value>* rbt;
public:
myMap();
~myMap();
public:
RBTNode<Key, Value>* begin();
RBTNode<Key, Value>* end();
void clear();
void insert( Key key, Value value );
void erase( Key key );
unsigned int size();
RBTNode<Key, Value>* find( Key key );
bool empty();
Value& operator[] ( Key key );
};
#include "myMap.cpp"
#endif
// myMap.cpp
template<class Key, class Value>
myMap<Key, Value>::myMap()
{
rbt = new RBTree<Key, Value>();
}
template<class Key, class Value>
myMap<Key, Value>::~myMap()
{
delete rbt;
}
template<class Key, class Value>
RBTNode<Key, Value>* myMap<Key, Value>::begin()
{
return rbt->begin();
}
template<class Key, class Value>
RBTNode<Key, Value>* myMap<Key, Value>::end()
{
return rbt->end();
}
template<class Key, class Value>
void myMap<Key, Value>::clear()
{
rbt->clear();
}
template<class Key, class Value>
void myMap<Key, Value>::insert( Key key, Value value )
{
rbt->insert( key, value );
}
template<class Key, class Value>
void myMap<Key, Value>::erase( Key key )
{
rbt->erase( key );
}
template<class Key, class Value>
unsigned int myMap<Key, Value>::size()
{
return rbt->size();
}
template<class Key, class Value>
RBTNode<Key, Value>* myMap<Key, Value>::find( Key key )
{
return find( key );
}
template<class Key, class Value>
bool myMap<Key, Value>::empty()
{
return rbt->empty();
}
template<class Key, class Value>
Value& myMap<Key, Value>::operator[] ( Key key )
{
return rbt->insertUnique( key )->value;
}
测试
这里还添加了一个简单的测试
#include "rbTree.h"
#include "mySet.h"
#include "myMap.h"
#include <iostream>
#include <string>
using namespace std;
int main( int argc, char* argv[] )
{
cout << "set test" << endl;
mySet<int> s;
s.insert(1);
cout << (s.find(1))->key << endl;
s.insert(10);
cout << (s.end())->key << endl;
s.insert(23);
cout << (s.begin())->key << endl;
s.erase(23);
cout << (s.end())->key << endl;
cout << endl << "map test" << endl;
myMap<int, int> m;
m.insert(1, 100);
m[5] = 132;
m.insert(3, 11);
m.insert(11, 44);
cout << "m[5]=" << m[5] << endl;
cout << "m[3]=" << m[3] << endl;
m.erase(5);
m.erase(100);
cout << endl << "rbTree test" << endl;
RBTree<int, int> tree;
string option;
for (int i=1; i<=10000; i++)
{
tree.insert( i );
}
for (int i=1; i<=10000; i++)
{
tree.erase( i );
}
while( true )
{
cout << "> ";
cin >> option;
if ( option == "insert" )
{
int k, val;
cin >> k >> val;
tree.insert( k, val );
cout << "finish insert" << endl;
tree.isRBT();
}
else if ( option == "erase" )
{
int val;
cin >> val;
tree.erase( val );
cout << "finish erase" << endl;
tree.isRBT();
}
else if ( option == "draw" )
{
tree.draw();
}
else if ( option == "exit" )
{
break;
}
}
return 0;
}