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

typedef int type;
typedef struct bst                                                                  //创建结构体
{
	type data;
	struct bst *left, *right;
	struct bst *parent;
}node, *tree;



static node* create_node(type data, node *left, node *right, node *parent)                       //创建结点
{
	node *p;
	p = (node*)malloc(sizeof(node));

	p->left = left;
	p->right = right;
	p->parent = parent;
	p->data = data;
	/* printf("创造结点完毕");*/
	return p;

}

node* search_(tree x, type key)
{
	if (x == NULL || x->data == key)
	{
		return x;
	}

	if (key < x->data)
	{

		return search_(x->left, key);
	}
	else

	{
		return search_(x->right, key);
	}


}                                                                  //递归查找


node* search(tree y, type key)
{

	while (y != NULL && y->data != key)
	{
		if (y->data < key)
			y = y->right;
		else
			y = y->left;
	}
	return y;
}                                                              //迭代查找


node* max(tree m)                       //最大值
{

	if (m == NULL)
		return NULL;
	while (m->right != NULL)
	{
		m = m->right;
	}
	return m;
}

node* min(tree m)                     //最小值
{

	if (m == NULL)
		return NULL;
	while (m->left != NULL)
	{
		m = m->left;
	}
	return m;
}

node* successor(node *s)           //后继
{


	if (s->right != NULL)             //结点右子树非空

		return  min(s->right);
	

	else
	{
		node* p = s->parent;                //结点是左孩子，后继就是他的父节点
		while (p != NULL && p->right == s)
		{                                       //结点是右孩子，向上查找，直到遇到一个有左孩子的父节点，那就是后继
			{
				s = p;
				p = p->parent;
			}

		}
		return p;
	}
	
}

node* insert(tree t, node *z)              //将建好的结点插入进二叉树里
{
	node *y = NULL;
	node *i;
	i = t;

	while (i != NULL)
	{
		y = i;                        //循环完了之后y是i的父节点
		if (i->data < z->data)
			i = i->right;
		else
			i = i->left;
	}
	z->parent = y;
	if (y == NULL)                         //整棵树在插入之前都是空的
		t = z;
	else if (z->data < y->data)
		y->left = z;
	else
		y->right = z;

	return t;



}

node* insert_(tree t, type k)                    //建立一个结点，没有连接
{
	node *z;
	z = create_node(k, NULL, NULL, NULL);


	return  insert(t, z);


}



node* deletes(tree d, node* z)                                           //删除
{
	tree x = NULL, y = NULL;

	if (z->left == NULL || z->right == NULL)                            //z至多有一个子女 
		y = z;
	else                                                                 //z有两个子女
		y = successor(z);
	if (y->left != NULL)                                                //y（也就是z，或z的后继）如果有子女，将它赋给x
		x = y->left;
	else
		x = y->right;
	if (x != NULL)                                                       //x如果得到了y赋的值(也就是z的子女或者后继的子女)
		x->parent = y->parent;
	if (y->parent == NULL)                                               //如果y是根节点
		d = x;
	else if (y == y->parent->left)                                         //如果y是左子女
		y->parent->left = x;
	else                                                                   //如果y是右子女
		y->parent->right = x;
	if (y != z)                                                            //y不等于z就是等于后继，z有两个子女的情况，就把后继的值拿给z
		z->data = y->data;
	return d;

}

node* delete_(tree t, type k)
{
	node* z=NULL;
	z = search_(t, k);

	if (z != NULL)
	{
		printf("查找");
		t = deletes(t, z);
		printf("删除完了");
	}
	else
		printf("无此元素");

	return t;
}


void print_tree(tree t)                        //中序遍历打印
{
	if (t)
	{
		print_tree(t->left);
		printf("%d ", t->data);
		print_tree(t->right);
	}
}


int main()
{
	int i;
	tree zz = NULL, yy = NULL,kk=NULL,gg=NULL;
	type k;
	int a[12] = { 15,5,16,3,12,10,13,6,7,20,18,23 };
	printf("\n原来的数字是：----------------------------------------");
	for (i = 0; i<12; i++)
	{
		printf("%d ", a[i]);
		zz = insert_(zz, a[i]);

	}
	/* printf("插入完毕");*/
	printf("\n中序遍历结果是：------------------------------------");
	print_tree(zz);
	printf("\n最大值是：-------------------------------------------");
	printf("%d ", max(zz)->data);
	printf("\n请输入要查找的值：--------------------------------");
	scanf_s("%d", &k);
	search_(zz, k);
	if (search_(zz, k) != NULL)
		printf("查找成功");
	else
		printf("无此元素");
	printf("\n要查找的后继是：---------------------------------");
	scanf_s("%d", &k);
	kk=search_(zz, k);
	gg=successor(kk);
	printf("%d", gg->data);
	printf("\n要删除的值是：---------------------------------------");
	scanf_s("%d", &k);
	yy = delete_(zz, k);
	print_tree(yy);
	printf("\n要插入的值是：--------------------------------------");
	scanf_s("%d", &k);
	insert_(zz, k);
	print_tree(zz);

}

参照了算法导论的伪代码和https://www.cnblogs.com/skywang12345/p/3576328.html这位博主的代码
感觉自己主函数写得好乱。。。。