二叉平衡查找树AvlTree（C实现）

二叉平衡查找树即是一棵树中所有节点的左右子树高度差不超过1的查找树
头文件——————————————————————————————
#ifndef _AVLTREE_H_
#define _AVLTREE_H_
#include <stdlib.h>
#include <iomanip>
#include <iostream>

typedef struct AvlNode *Position;
typedef Position AvlTree;
#define Element int
struct AvlNode
{
     Element data;
     int height;//叶子节点高度定义为0，其父节点为1以此类推
     AvlTree left;
     AvlTree right;
};

static int Height(AvlTree avl);
void SwapAvlNode(Position *p1, Position *p2);
Position GetNotBalancedNode(AvlTree avl);
void MakeEmpty(AvlTree* pavl);
Position Find(Element x, AvlTree avl);
Position FindMin(AvlTree avl);
Position FindMax(AvlTree avl);
void Insert(Element x, AvlTree* pavl);
void Delete(Element x, AvlTree* pavl);
Element Retrieve(Position p);
void SingleRotateWithLeftLeft(Position *pK2);
void SingleRotateWithRightRight(Position *pK2);
void DoubleRotateWithLeftRight(Position *pK3);
void DoubleRotateWithRightLeft(Position *pK3);
void PrintTree(AvlTree avl, int Depth, int ctrl);
#endif
源文件————————————————————————————————
#include "./AvlTree.h"

int Max(int a, int b)
{
     if(a <= b)
          return b;
     return a;
}
void SwapAvlNode(Position *p1, Position *p2)
{
     Position tmp = *p1;
     *p1 = *p2;
     *p2 = tmp;
}
int Abs(int a)
{
     if(a < 0) return -a;
     return a;
}
static int Height(AvlTree avl)
{
     if(NULL == avl)
          return -1;
     else
          return avl->height;
}
Position GetNotBalancedNode(AvlTree avl)
{
     if(NULL == avl)
          return NULL;
     else
     {
          if(Height(avl->left) - Height(avl->right) == Abs(2))//not balanced
               return avl;
          else
          {
               Position res = GetNotBalancedNode(avl->left);
               if(NULL != res)//avl->left is not balanced
                    return res;
               else
                    return GetNotBalancedNode(avl->right);
          }
     }
}
void MakeEmpty(AvlTree* pavl)
{
     if(NULL != (*pavl))
     {
          MakeEmpty(&((*pavl)->left));
          MakeEmpty(&((*pavl)->right));
          free(*pavl);
          *pavl = NULL;
     }
}
Position Find(Element x, AvlTree avl)
{
     Position pos = avl;
     while(NULL != pos)
     {
          if(x < Retrieve(pos))
               pos = pos->left;
          else if(x > Retrieve(pos))
               pos = pos->right;
          else
               break;
     }
     return pos;
}
Position FindMin(AvlTree avl)
{
     while(NULL != avl && NULL != avl->left)
          avl = avl->left;
     return avl;
}
Position FindMax(AvlTree avl)
{
     while(NULL != avl && NULL != avl->right)
          avl = avl->right;
     return avl;
}
void Insert(Element x, AvlTree* pavl)
{
     if(NULL == (*pavl))
     {
          Position tmp = (Position)malloc(sizeof(struct AvlNode));
          if(NULL == tmp)
               return ;
          tmp->data = x;
          tmp->height = 0;
          tmp->left = tmp->right = NULL;
          *pavl = tmp;
     }
     else
     {
          if(x < Retrieve(*pavl))//在*pavl的左儿子上插入
          {
               Insert(x, &((*pavl)->left));
               if(Height((*pavl)->left) - Height((*pavl)->right) == 2)//不平衡
               {
                    if(x < Retrieve((*pavl)->left))//左儿子的左子树
                         SingleRotateWithLeftLeft(pavl);
                    else//左儿子的右子树
                         DoubleRotateWithLeftRight(pavl);
               }
          }
          else if(x > Retrieve(*pavl))//在*pavl的右儿子上插入
          {
               Insert(x, &((*pavl)->right));
               if(Height((*pavl)->right) - Height((*pavl)->left) == 2)//不平衡
               {
                    if(x > Retrieve((*pavl)->right))//右儿子的右子树
                         SingleRotateWithRightRight(pavl);
                    else//右儿子的左子树
                         DoubleRotateWithRightLeft(pavl);
               }
          }
     }
     (*pavl)->height = Max(Height((*pavl)->left), Height((*pavl)->right)) + 1;
}
void Delete(Element x, AvlTree* pavl)
{
     if(NULL == *pavl)
          return ;
     if(x < Retrieve((*pavl)))//go left
          Delete(x, &((*pavl)->left));
     else if(x > Retrieve((*pavl)))//go right
          Delete(x, &((*pavl)->right));
     else if(NULL != (*pavl)->left && NULL != (*pavl)->right)//*pavl has two children
     {
          //利用右子树的最小值tmp->data来替代被删除的节点上的值x，然后在右子树上递归的删除值tmp->data
          Position tmp = FindMin((*pavl)->right);
          (*pavl)->data = tmp->data;
          Delete(tmp->data, &((*pavl)->right));
     }
     else//*pavl has none or one child
     {
          Position tmp = *pavl;
          if(NULL == (*pavl)->left)//*pavl has right child
               *pavl = (*pavl)->right;
          else if(NULL == (*pavl)->right)//*pavl has left child
               *pavl = (*pavl)->left;
          free(tmp);
     }
     if(NULL != *pavl)//最后更新*pavl节点上的高度
     {
          (*pavl)->height = Max(Height((*pavl)->left), Height((*pavl)->right)) + 1;
          if(2 == Height((*pavl)->left) - Height((*pavl)->right))//not balanced
          {
               if(NULL == (*pavl)->left->right)
                    SingleRotateWithLeftLeft(pavl);
               else
                    DoubleRotateWithLeftRight(pavl);
          }
          else if(2 == Height((*pavl)->right) - Height((*pavl)->left))//not balance
          {
               if(NULL == (*pavl)->right->left)
                    SingleRotateWithRightRight(pavl);
               else
                    DoubleRotateWithRightLeft(pavl);
          }
     }
}
Element Retrieve(Position p)
{
     return p->data;
}
void SingleRotateWithLeftLeft(Position *pK2)
{
     Position k2 = *pK2;
     Position k1 = k2->left;
     k2->left = k1->right;
     k1->right = k2;
     k1->height = Max(Height(k1->left), Height(k2)) + 1;
     k2->height = Max(Height(k2->left), Height(k2->right)) + 1;
     *pK2 = k1;
}
void SingleRotateWithRightRight(Position *pK2)
{
     Position k2 = *pK2;
     Position k1 = k2->right;
     k2->right = k1->left;
     k1->left = k2;
     k1->height = Max(Height(k2), Height(k1->right)) + 1;
     k2->height = Max(Height(k2->left), Height(k2->right)) + 1;
     *pK2 = k1;
}
void DoubleRotateWithLeftRight(Position *pK3)
{
     SingleRotateWithRightRight(&((*pK3)->left));
     SingleRotateWithLeftLeft(pK3);
}
void DoubleRotateWithRightLeft(Position *pK3)
{
     SingleRotateWithLeftLeft(&((*pK3)->right));
     SingleRotateWithRightRight(pK3);
}
void PrintTree(AvlTree avl, int Depth, int ctrl)//ctrl:0=root 1=left 2=right
{

     if(NULL != avl)
     {
          std::cout<<std::setw(Depth);
          if(0 == ctrl)
               std::cout<<"rt:";
          else if(1 == ctrl)
               std::cout<<"l";
          else if(2 == ctrl)
               std::cout<<"r";
          std::cout<<avl->data<<std::endl;
          PrintTree(avl->left, Depth+3, 1);
          PrintTree(avl->right, Depth+3, 2);
     }
}