纯C语言实现的AVL树（插入&删除&前序遍历输出）

#include <stdio.h>
#include <stdlib.h>

#define MAX(a,b) ((a)>(b)?(a):(b)) //比较大小
#define Height(p) ((p==NULL)?0:(((Tree)(p))->height)) // 求高度

typedef struct Node* Tree;

struct Node
{
int Key;
int height;
Tree Left;
Tree Right;
};

Tree nodeCreate(int Key) //创建节点
{
Tree p = (Tree)malloc(sizeof(struct Node));
if(p == NULL)return p;
p->height = 0;
p->Key = Key;
p->Left = NULL;
p->Right = NULL;
return p;
}

Tree lL(Tree k2)
{
Tree k1 = k2->Left;
k2->Left = k1->Right;
k1->Right = k2;
k2->height = MAX(Height(k2->Left) , Height(k2->Right))+1;
k1->height = MAX(Height(k1->Left) , Height(k1->Right))+1;

return k1;
}

Tree rR(Tree k1)
{
Tree k2 = k1->Right;
k1->Right = k2->Left;
k2<
4000
span class="hljs-subst">->Left = k1;
k1->height = MAX(Height(k1->Left) , Height(k1->Right))+1;
k2->height = MAX(Height(k2->Left) , Height(k2->Right))+1;

return k2;
}

Tree lR(Tree k3)
{
k3->Left = rR(k3->Left);
return lL(k3);
}

Tree rL(Tree k3)
{
k3->Right = lL(k3->Right);
return rR(k3);
}

Tree nodeInsert(Tree root,int data) //插入
{
if(root == NULL)
{
root = nodeCreate(data);
if(root == NULL)
{
printf("ERROR of the memory!!!\n");
return NULL;
}
}
else if(root->Key == data)
{
printf("ERROR of the data!!!\n");
}
else if(root->Key > data)
{
root->Left = nodeInsert(root->Left,data);
if(Height(root->Left) - Height(root->Right) == 2)
{
if(data < root->Left->Key)
{
root = lL(root);
}
else if(data >= root->Left->Key)
{
root = lR(root);
}
}
}
else if(root->Key < data)
{
root->Right = nodeInsert(root->Right,data);
if(Height(root->Right) - Height(root->Left) == 2)
{
if(data > root->Right->Key)
{
root = rR(root);
}
else if(data <= root->Right->Key)
{
root = rL(root);
}
}
}

root->height = MAX( Height(root->Left) , Height(root->Right) )+1;

return root;
}

Tree nodeDelete(Tree root,int data) //删除
{
if(root == NULL)
{
printf("Don`t have this data!!!\n");
return NULL;
}

if(data < root->Key)
{
root->Left = nodeDelete(root->Left,data);
if(Height(root->Right) - Height(root->Left) == 2)
{
if(Height(root->Right->Left) > Height(root->Right->Right))
{
root = rL(root);
}
else root = rR(root);
}
}
else if(data > root->Key)
{
root->Right = nodeDelete(root->Right,data);
if(Height(root->Left) - Height(root->Right) == 2)
{
if(Height(root->Left->Left) > Height(root->Left->Right))
{
root = lL(root);
}
else root = lR(root);
}
}
else if(data == root->Key)
{
if(root->Left && root->Right)
{
if(Height(root->Left) > Height(root->Right))
{
Tree max = root->Left;
Tree tr = root;
int flag = 1;
while(max->Right)
{
if(flag)
{
flag = 0;
tr = tr->Left;
}
else tr = tr->Right;
max = max->Right;
}
root->Key = max->Key;
if(flag)tr->Left = NULL;
else tr->Right = NULL;
free(max);
}
else
{
Tree max = root->Right;
Tree tr = root;
int flag = 1;
while(max->Left)
{
if(flag)
{
flag = 0;
tr = tr->Right;
}
else tr = tr->Left;
max = max->Left;
}
root->Key = max->Key;
if(flag)tr->Right = NULL;
else tr->Left = NULL;
free(max);
}
}
else
{
Tree t = root;
root = (root->Left ? root->Left : root->Right);
free(t);
}
}

return root;
}

void preorderPrintf(Tree tree) // 前序遍历
{
if(tree != NULL)
{
printf("%d ", tree->Key);
preorderPrintf(tree->Left);
preorderPrintf(tree->Right);
}
}

int main()
{
Tree root = NULL;

int N;
scanf("%d",&N);
while(N--)
{
int mid;
scanf("%d",&mid);
root = nodeInsert(root,mid);
}

int M;
scanf("%d",&M);
while(M--)
{
int mid;
scanf("%d",&mid);
root = nodeDelete(root,mid);
}

preorderPrintf(root);

return 0;
}