careercup-树与图 4.6

#include<iostream>
#include<new>
using namespace std;

struct BinarySearchTree
{
    int elem;
    BinarySearchTree *parent;
    BinarySearchTree *left;
    BinarySearchTree *right;
    BinarySearchTree(int x):elem(x),parent(NULL),left(NULL),right(NULL) {}
};

void insert(BinarySearchTree *&root,int z)
{
    BinarySearchTree *y=new BinarySearchTree(z);
    if(root==NULL)
    {
        root=y;
        return;
    }
    else if(root->left==NULL&&z<root->elem)
    {
        root->left=y;
        y->parent=root;
        return;
    }
    else if(root->right==NULL&&z>root->elem)
    {
        root->right=y;
        y->parent=root;
        return;
    }
    if(z<root->elem)
        insert(root->left,z);
    else
        insert(root->right,z);
}

void createBST(BinarySearchTree *&root)
{
    int arr[10]= {29,4,6,1,8,3,0,78,23,89};
    for(auto a:arr)
        insert(root,a);
}

void inorder(BinarySearchTree *root)
{
    if(root)
    {
        inorder(root->left);
        cout<<root->elem<<" ";
        inorder(root->right);
    }
}

BinarySearchTree* findMin(BinarySearchTree *root)
{
    if(root==NULL||!root->left)
        return root;
    while(root->left)
    {
        root=root->left;
    }
    return root;
}

BinarySearchTree* findMax(BinarySearchTree *root)
{
    if(root==NULL||!root->right)
        return root;
    while(root->right)
    {
        root=root->right;
    }
    return root;
}

BinarySearchTree* findProcessor(BinarySearchTree *root,BinarySearchTree* x)
{
    if(x->left)
        return findMax(x->left);
    BinarySearchTree *y=x->parent;
    while(y&&y->left==x)
    {
        x=y;
        y=x->parent;
    }
    return y;
}

BinarySearchTree* findSuccessor(BinarySearchTree *x)
{
    if(x->right)
        return findMin(x->right);
    BinarySearchTree *y=x->parent;
    while(y&&y->right==x)
    {
        x=y;
        y=x->parent;
    }
    return y;
}

int main()
{
    BinarySearchTree *root=NULL;
    createBST(root);
    inorder(root);
}