平衡二叉树link

https://baike.baidu.com/item/%E5%B9%B3%E8%A1%A1%E4%BA%8C%E5%8F%89%E6%A0%91/10421057?fr=aladdin

https://www.cnblogs.com/huangxincheng/archive/2012/07/22/2603956.html

 http://blog.csdn.net/programmingring/article/details/37969745

#include <stdio.h>
#include <stdlib.h>
/************************************************************************/
/*                    平衡二叉树---AVL                                  */
/************************************************************************/
#define LH +1
#define EH  0
#define RH -1
typedef int ElemType;
typedef struct BSTNode{
    ElemType data;
    int bf;//balance flag
    struct BSTNode *lchild,*rchild;
}*PBSTree;

void R_Rotate(PBSTree* p)
{
    PBSTree lc = (*p)->lchild;
    (*p)->lchild = lc->rchild;
    lc->rchild = *p;
    *p = lc;
}

void L_Rotate(PBSTree* p)
{
    PBSTree rc = (*p)->rchild;
    (*p)->rchild = rc->lchild;
    rc->lchild = *p;
    *p = rc;
}

void LeftBalance(PBSTree* T)
{
    PBSTree lc,rd;
    lc = (*T)->lchild;
    switch (lc->bf)
    {
    case LH:
        (*T)->bf = lc->bf = EH;
        R_Rotate(T);
        break;
    case RH:
        rd = lc->rchild;
        switch(rd->bf)
        {
        case LH:
            (*T)->bf = RH;
            lc->bf = EH;
            break;
        case EH:
            (*T)->bf = lc->bf = EH;
            break;
        case RH:
            (*T)->bf = EH;
            lc->bf = LH;
            break;
        }
        rd->bf = EH;
        L_Rotate(&(*T)->lchild);
        R_Rotate(T);
        break;
    }
}

void RightBalance(PBSTree* T)
{
    PBSTree lc,rd;
    lc= (*T)->rchild;
    switch (lc->bf)
    {
    case RH:
        (*T)->bf = lc->bf = EH;
        L_Rotate(T);
        break;
    case LH:
        rd = lc->lchild;
        switch(rd->bf)
        {
        case LH:
            (*T)->bf = EH;
            lc->bf = RH;
            break;
        case EH:
            (*T)->bf = lc->bf = EH;
            break;
        case RH:
            (*T)->bf = EH;
            lc->bf = LH;
            break;
        }
        rd->bf = EH;
        R_Rotate(&(*T)->rchild);
        L_Rotate(T);
        break;
    }
}

int InsertAVL(PBSTree* T,ElemType e,bool* taller)
{
    if ((*T)==NULL)
    {
        (*T)=(PBSTree)malloc(sizeof(BSTNode));
        (*T)->bf = EH;
        (*T)->data = e;
        (*T)->lchild = NULL;
        (*T)->rchild = NULL;
    }
    else if (e == (*T)->data)
    {
        *taller = false;
        return 0;
    }
    else if (e < (*T)->data)
    {
        if(!InsertAVL(&(*T)->lchild,e,taller))
            return 0;
        if(*taller)
        {
            switch ((*T)->bf)
            {
            case LH:
                LeftBalance(T);
                *taller = false;
                break;
            case  EH:
                (*T)->bf = LH;
                *taller = true;
                break;
            case RH:
                (*T)->bf = EH;
                *taller = false;
                break;
            }
        }
    }
    else
    {
        if(!InsertAVL(&(*T)->rchild,e,taller))
            return 0;
        if (*taller)
        {
            switch ((*T)->bf)
            {
            case LH:
                (*T)->bf = EH;
                *taller = false;
                break;
            case EH:
                (*T)->bf = RH;
                *taller = true;
                break;
            case  RH:
                RightBalance(T);
                *taller = false;
                break;
            }
        }
    }
    return 1;
}

bool FindNode(PBSTree root,ElemType e,PBSTree* pos)
{
    PBSTree pt = root;
    (*pos) = NULL;
    while(pt)
    {
        if (pt->data == e)
        {
            //找到节点，pos指向该节点并返回true
            (*pos) = pt;
            return true;
        }
        else if (pt->data>e)
        {
            pt = pt->lchild;
        }
        else
            pt = pt->rchild;
    }
    return false;
}
void InorderTra(PBSTree root)
{
    if(root->lchild)
        InorderTra(root->lchild);
    printf("%d ",root->data);
    if(root->rchild)
        InorderTra(root->rchild);
}

int main()
{
    int i,nArr[] = {1,23,45,34,98,9,4,35,23};
    PBSTree root=NULL,pos;
    bool taller;
    for (i=0;i<9;i++)
    {
        InsertAVL(&root,nArr[i],&taller);
    }
    InorderTra(root);
    if(FindNode(root,103,&pos))
        printf("
%d
",pos->data);
    else
        printf("
Not find this Node
");
    return 0;
}