#include <stdio.h>
#include "bi_sort_tree.h"

#define KeyType ElemType
typedef void (*Visit)(ElemType e);

int g_arr[20] = {45, 24, 12, 53, 45, 12, 24, 90, 70}; 

/* f是T的父节点，如果能找到节点，p是该节点的指针，否则p指向最后搜索节点的指针 */
Status SearchBST(BiTree T, KeyType key, BiTree f, BiTree *p)
{
	if (!T) 
	{
		*p = f; // f 不一定是Null.
		return FAIL;
	}

	if (key == T->data)
	{
		*p = T;
		return SUCCESS;
	}
	else if (key > T->data)
	{
		return SearchBST(T->rchild, key, T, p);	 
	}
	else
	{
		return SearchBST(T->lchild, key, T, p);
	}
}


Status InsertBST(BiTree *T, KeyType key)
{
	BiTree p;
	BiTree s;

	if (SearchBST(*T, key, NULL, &p)) 
	{
		s = (BiTree)malloc(sizeof(BiTNode));	
		if (NULL == s)
		{
			printf("%s: malloc error!\n", __FUNCTION__);	
			return ERROR;
		}

		s->lchild = NULL;
		s->rchild = NULL;
		s->data = key;

		if (!p)
		{
			*T = s;
		}
		else if (key > p->data)
		{
			p->rchild = s;
		}	
		else
		{
			p->lchild = s;
		}

		return SUCCESS;
	}
	else
	{
		printf("BST has the same key(%d)!\n", key);
		return FAIL;
	}
}

Status delete(BiTree *p)
{
	BiTree q;
	BiTree s;

	if (!((*p)->lchild))		
	{
		q = *p;
		*p = (*p)->rchild;
		free(q);
	}
	else if (!((*p)->rchild))
	{
		q = *p;
		*p = (*p)->lchild;
		free(q);
	}
	else
	{
#if 0 // method 1
		q = *p;	
		s = (*p)->lchild;	

		while (s->rchild)
		{
			s = s->rchild;	
		}

		s->rchild = (*p)->rchild;
		*p = (*p)->lchild;

		free(q);
#else //method 2
		q = *p;
		s =	(*p)->lchild;

		while (s->rchild)
		{
			q = s;
			s = s->rchild;
		}
	   
	    (*p)->data = s->data;

		if (q != *p)
		{
			q->rchild = s->lchild;	
		}
		else
		{
			q->lchild = s->lchild;	
		}
		
		free(q);
#endif
	}
}

Status DeleteBST(BiTree *T,  KeyType key)
{
	if (!(*T))
	{
		printf("don't find the node(key=%d), so can't delete it!\n", key);
		return FAIL;
	}
	else
	{
		if ((*T)->data == key) 
		{
		    return delete(T);	
		}	
		else if ((*T)->data > key)
		{
			return DeleteBST(&(*T)->lchild, key);
		}
		else
		{
			return DeleteBST(&(*T)->rchild, key);
		}
	}
}	

void visit(ElemType e)
{
	printf("e = %d, " ,e);
	return;
}

void traverse(BiTree T, Visit v)
{
	if (T)
	{
		traverse(T->lchild, v);
		(*v)(T->data);
		traverse(T->rchild, v);
	}

	return;
}

void CreatBST(BiTree *T, int n)
{
	int i;

	for (i = 0; i < n; i++)
	{
		InsertBST(T, g_arr[i]); 
	}

	return;
}

int main(void)
{
	BiTree T = NULL;
	KeyType key = 24;

	CreatBST(&T, 8);
	traverse(T, visit);

	DeleteBST(&T, key); 
	printf("after delete key=%d!\n", key);
	traverse(T, visit);

	return 0;
}