二叉树查找

1.对象：无重复数字

2.查找代码

Bts_node* search_Bts(Bts_node *bt,int k)
{
    if(bt==NULL||bt->data==k)
        return bt;
    if(k<bt->data)
        return search_Bts(bt->lchild,k);
    else
        return search_Bts(bt->rchild,k);
 }

3.删除代码

void delete2(Bts_node *p,Bts_node *&r)
{
    Bts_node *q;
    if(r->rchild!=NULL)//找到最大的节点（右边大），用while也许也行
       delete2(p,r->rchild);
    else
    {
        p->data=r->data;
        q=r;
        r=r->lchild;
        delete(q);
    }
}
void delete1(Bts_node *&p)
{
    Bts_node *q;
    if(p->rchild==NULL)//只有左子树
    {
        q=p;
        p=p->lchild;
        delete(q);
    }
    else if(p->lchild==NULL)//只有右子树
    {
        q=p;
        p=p->rchild;
        delete(q);
    }
    else
        delete2(p,p->lchild);
}
bool delete_Bts(Bts_node *&bt,int k)
{
    if(bt==NULL)
      return false;
    else
    {
        if(k<bt->data)
            return delete_Bts(bt->lchild,k);
        else if(k>bt->data)
            return delete_Bts(bt->rchild,k);
        else
        {
            delete1(bt);
            return true;
        } 
    }
}

4.实例：

#include<iostream>
using namespace std;
struct Bts_node
{
    int data;
    Bts_node *lchild,*rchild;
};
bool insert_Bts(Bts_node *&bt,int k)
{
    if(bt==NULL)
    {
        bt=new Bts_node;
        bt->data=k;
        bt->lchild=bt->rchild=NULL;
    }
    if(k==bt->data)
       return false;
    else
    {
        if(k>bt->data)
           insert_Bts(bt->rchild,k);
        else
           insert_Bts(bt->lchild,k);
    }
}
Bts_node *create_Bts(int n)
{
    Bts_node *bt=NULL;
    for(int i=0;i<n;i++)
    {
        int temp;
        cin>>temp;
        insert_Bts(bt,temp);
    }
    return bt;
}
Bts_node* search_Bts(Bts_node *bt,int k,Bts_node *f,Bts_node *&f1)
{
    if(bt==NULL)
    {
        f1=NULL;
        return NULL;
    }
    else if(bt->data==k)
    {
        f1=f;
        return bt;
    }
    else if(k<bt->data)
        return search_Bts(bt->lchild,k,bt,f1);
    else
        return search_Bts(bt->rchild,k,bt,f1);
}
      void print(Bts_node *b1)
        {
            if(b1!=NULL)
            {
                cout<<b1->data;
                if(b1->lchild!=NULL||b1->rchild!=NULL)
                {
                    cout<<"(";
                    print(b1->lchild);
                    if(b1->rchild!=NULL)
                    {
                        cout<<",";
                        print(b1->rchild);
                    }
                    cout<<")";
                }
            }
        }
Bts_node* search_Bts(Bts_node *bt,int k)
{
    if(bt==NULL||bt->data==k)
        return bt;
    if(k<bt->data)
        return search_Bts(bt->lchild,k);
    else
        return search_Bts(bt->rchild,k);
 }

int main()
{
    Bts_node *bt,*f1;
    int n;
    cout<<"n=";
    cin>>n;
    bt=create_Bts(n);
    int k;
    cout<<"k=";
    cin>>k; 
    cout<<search_Bts(bt,k,NULL,f1)->data<<endl;//找双亲 +k
    cout<<search_Bts(bt,k)->data<<endl;//只 找 K 
    print(bt);
    delete_Bts(bt,k);
    print(bt);
    return 0;
}