#include"iostream"
using namespace std;
struct BST
{
    int v;
    BST *Ls,*Rs;
};
BST *Find(BST *u,int v)
{
    if(u==NULL)return NULL;
    if(u->v>v)return Find(u->Ls,v);
    else if(u->v<v)return Find(u->Rs,v);
    else return u;
}
bool Insert(BST *&u,int v)
{
    if(u==NULL)
    {
        u=new BST;
        u->v=v;
        u->Ls=u->Rs=NULL;
        return true;
    }
    else if(u->v>v)return Insert(u->Ls,v);
    else if(u->v<v)return Insert(u->Rs,v);
    return false;
}

BST *findmin(BST *u)
{
    if(u==NULL)return NULL;
    else if(u->Ls==NULL)return u;
    else return findmin(u->Ls);
}
BST *findmax(BST *u)
{
    if(u==NULL)return NULL;
    else if(u->Rs==NULL)return u;
    else return findmax(u->Rs);
}
bool Delete(BST *&u,int v)
{
    if(u==NULL)return false;
    else if(u->v>v)return Delete(u->Ls,v);
    else if(u->v<v)return Delete(u->Rs,v);

    else
    {
        if(u->Ls&&u->Rs)
        {
            BST *temp=findmax(u->Ls);
            u->v=temp->v;
            return Delete(temp,temp->v);
        }
        else
        {
            if(u->Ls)u=u->Ls;
            else if(u->Rs)u=u->Rs;
            return true;
        }
    }
}
void PreOrderTraverse(BST *T)   //递归前序 
{  
    if(T==NULL)  
        return;  
    printf("%d ",T->v);  
    PreOrderTraverse(T->Ls);  
    PreOrderTraverse(T->Rs);  
}  
int main()
{
    BST *root=NULL;  
    Insert(root,5);
    Insert(root,6);
    Insert(root,7);
    Insert(root,8);
    Insert(root,9);
    Insert(root,10);

// BST *&p=root;
// p=p->Rs;
// BST *pp=root;
// cout<<pp->v<<"\n";

    BST *p=root;
    p->v=9;
    cout<<root->v<<"\n"; 


}