二叉树排序查找
#include <stdio.h>
#include <malloc.h>
typedef int KeyType;
typedef char ElemType[10];
typedef struct tnode
{
KeyType key;
ElemType data;
struct tnode *lchild,*rchild;
} BSTNode;
BSTNode *BSTSearch(BSTNode *bt,KeyType k)
{
BSTNode *p=bt;
while (p!=NULL && p->key!=k)
{
if (k<p->key)
p=p->lchild;
else
p=p->rchild;
}
return(p);
}
int BSTInsert(BSTNode *&bt,KeyType k)
{
BSTNode *f,*p=bt;
while (p!=NULL)
{
if (p->key==k)
return(0);
f=p;
if (p->key>k)
p=p->lchild;
else
p=p->rchild;
}
p=(BSTNode *)malloc(sizeof(BSTNode));
p->key=k;
p->lchild=p->rchild=NULL;
if (bt==NULL)
bt=p;
else if (k<f->key)
f->lchild=p;
else
f->rchild=p;
return(1);
}
void CreateBST(BSTNode *&bt,KeyType str[],int n)
{
bt=NULL;
int i=0;
while (i<n)
{
BSTInsert(bt,str[i]);
i++;
}
}
void DispBST(BSTNode *bt)
{
if (bt!=NULL)
{ printf("%d",bt->key);
if (bt->lchild!=NULL || bt->rchild!=NULL)
{ printf("(");
DispBST(bt->lchild);
if (bt->rchild!=NULL) printf(",");
DispBST(bt->rchild);
printf(")");
}
}
}
int BSTDelete(BSTNode *&bt,KeyType k)
{
BSTNode *p=bt,*f,*r,*f1;
f=NULL;
while (p!=NULL && p->key!=k)
{ f=p;
if (p->key>k)
p=p->lchild;
else
p=p->rchild;
}
if (p==NULL)
return(0);
else if (p->lchild==NULL)
{
if (f==NULL)
bt=p->rchild;
else if (f->lchild==p)
{ f->lchild=p->rchild;
free(p);
}
else if(f->rchild==p)
{ f->rchild=p->rchild;
free(p);
}
}
else if (p->rchild==NULL)
{
if (f==NULL)
bt=p->lchild;
if (f->lchild==p)
{ f->lchild=p->lchild;
free(p);
}
else if(f->rchild==p)
{ f->rchild=p->lchild;
free(p);
}
}
else
{
f1=p;r=p->lchild;
while (r->rchild!=NULL)
{ f1=r;
r=r->rchild;
}
if (f1->lchild==r)
f1->lchild=r->rchild;
else if (f1->rchild==r)
f1->rchild=r->lchild;
r->lchild=p->lchild;
r->rchild=p->rchild;
if (f==NULL)
bt=r;
else if (f->lchild==p)
f->lchild=r;
else
f->rchild=r;
free(p);
}
return(1);
}
void main()
{
BSTNode *bt=NULL,*p;
KeyType a[]={10,6,12,8,3,20,9,25,15},k;
int n=9;
CreateBST(bt,a,n);
printf("BST:");DispBST(bt);printf("\n");
k=9;
printf("查找关键字为%d的结点\n",k);
p=BSTSearch(bt,k);
if (p!=NULL)
printf("存在关键字为%d结点\n",k);
else
printf("不存在关键字为%d结点\n",k);
k=7;
printf("插入关键字为%d的结点\n",k);
BSTInsert(bt,k);
printf("BST:");DispBST(bt);printf("\n");
k=10;
printf("删除关键字为%d的结点\n",k);
BSTDelete(bt,k);
printf("BST:");DispBST(bt);printf("\n");
}