C ++ AVL Tree Deletion

Question

所以，我想从文本文件中获取输入，然后在AVL树中执行一些操作。我可以实现插入，但我不能在我的脑海中构建一个删除解决方案。你能帮助我吗？这是代码。

 #include<iostream>
 #include<cstdio>
 #include<sstream>
 #include<algorithm>
 #include <fstream>
 #include <stdlib.h>
 #include <array>
 #include <ctime>

  using namespace std;

  struct node
  {
      int data;
      int height;
      struct node *leftchild;
      struct node *rightchild;

  }*root;

 class avlTree
  {
      public:
      int height(node *);
      int difference(node *);
      node *rrtraversal(node *);
      node *lltraversal(node *);
      node *lrtraversal(node *);
      node *rltraversal(node *);
      node* balance(node *);
      node* insert(node *, int );
      void display(node *, int);
      node *del(node *, int);

      avlTree()
      {
        root = NULL;
      }
 };

int avlTree::height(node *temp)
{
    int h = 0;
    if (temp != NULL)
    {
        int l_height = height (temp->leftchild);
        int r_height = height (temp->rightchild);
        int max_height = max (l_height, r_height);
        h = max_height + 1;
    }
    return h;
}

int avlTree::difference(node *temp)
{
    int l_height = height (temp->leftchild);
    int r_height = height (temp->rightchild);
    int b_factor= l_height - r_height;
    return b_factor;
}

node *avlTree::rrtraversal(node *parent)
{
    node *temp;
    temp = parent->rightchild;
    parent->rightchild = temp->leftchild;
    temp->leftchild = parent;
    return temp;
}

node *avlTree::lltraversal(node *parent)
{
    node *temp;
    temp = parent->leftchild;
    parent->leftchild = temp->rightchild;
    temp->rightchild = parent;
    return temp;
}

node *avlTree::lrtraversal(node *parent)
{
    node *temp;
    temp = parent->leftchild;
    parent->leftchild = rrtraversal (temp);
    return lltraversal (parent);
}


node *avlTree::rltraversal(node *parent)
{
    node *temp;
    temp = parent->rightchild;
    parent->rightchild = lltraversal (temp);
    return rrtraversal (parent);
}


 node *avlTree::balance(node *temp)
{
    int bal_factor = difference (temp);
    if (bal_factor > 1)
    {
        if (difference (temp->leftchild) > 0)
            temp = lltraversal (temp);
        else
            temp = lrtraversal (temp);
    }
    else if (bal_factor < -1)
    {
        if (difference (temp->rightchild) > 0)
            temp = rltraversal (temp);
        else
            temp = rrtraversal (temp);
    }
    return temp;
}


node *avlTree::insert(node *root, int value)
{
    if (root == NULL)
    {
        root = new node;
        root->data = value;
        root->leftchild = NULL;
        root->rightchild = NULL;
        return root;
    }
    else if (value < root->data)
    {
        root->leftchild = insert(root->leftchild, value);
        root = balance (root);
    }
    else if (value >= root->data)
    {
        root->rightchild = insert(root->rightchild, value);
        root = balance (root);
    }
    return root;
}

void avlTree::display(node *ptr, int level)
{
    int i;
    if (ptr!=NULL)
    {
        display(ptr->rightchild, level + 1);
        printf("\n");
        for (i = 0; i < level && ptr != root; i++)
            cout<<"        ";
        cout<<ptr->data;
        display(ptr->leftchild, level + 1);
    }
}

node *avlTree::del(node *root, int x)
{
    node *d;

    if ( x < root->data){
        del(root->leftchild,x);

    }
    else if (x > root->data){
        del(root->rightchild,x);


    }
    else if ((root->leftchild == NULL) && (root->rightchild == NULL))
    {
        d=root;
        free(d);
        root=NULL;

    }
    else if (root->leftchild == NULL)
    {
        d=root;
        free(d);
        root= root->rightchild;

    }
    else if (root->rightchild == NULL)
    {
        d=root;
        root=root->leftchild;
        free(d);

    }

    return root;

}

int main()
{

    ifstream myFile("file.txt");
    int a = 0;
    std::array<string,512> arrayTest;
    int index = 0;
    string content;
    avlTree avl;

    while (myFile >> content){
        arrayTest[index] = content;
        index++;    
    }

    clock_t startTime = clock();

    for(a = 0; a < arrayTest.size();a++){
        if(arrayTest[a] == "i"){
        root = avl.insert(root, std::stoi(arrayTest[a+1]));
        }
    }

    avl.display(root,1);

    clock_t endTime = clock();
    clock_t clockTicksTaken = endTime - startTime;
    double timeInSeconds = clockTicksTaken / (double) CLOCKS_PER_SEC;

    cout << "\n\n" << timeInSeconds << " secs\n";

}

在文件中，内容是这样的。 i 1 i 2 i 3 i 4 i 5 d 3

如果程序看到i，它将执行插入操作。同样，如果它看到d，它将执行删除操作。

Answer 1

您是否尝试过free（）函数？

free(node);