Red-black tree の問題　デバックエラーになる　(C++)

実現したいこと

ExtendedRedBlackTree.hとExtendedRBTNode.hに変更を加えてプログラムを完成させたい

問題文

イメージ説明

ソースコード

問題で与えられているそれぞれのソースコードは、以下のURLにまとめておきましたので、ダウンロードできます。
ソースコード

問題を解くために直すprogram

ExtendedRBTNode.h

#ifndef EXTENDEDRBTNODE_H
#define EXTENDEDRBTNODE_H

#include "RBTNode.h"

class ExtendedRBTNode : public RBTNode {
private:
   int subtreeKeyCount;

public:
   ExtendedRBTNode(int nodeKey) : RBTNode(nodeKey) {
      subtreeKeyCount = 1;
   }
   
   virtual int GetSubtreeKeyCount() override {
      return subtreeKeyCount;
   }
   
   // Your code here
};

#endif

ExtendedRedBlackTree.h

#ifndef EXTENDEDREDBLACKTREE_H
#define EXTENDEDREDBLACKTREE_H

#include "RedBlackTree.h"
#include "ExtendedRBTNode.h"

class ExtendedRedBlackTree : public RedBlackTree {
protected:
   // Each node in an ExtendedRedBlackTree is an ExtendedRBTNode
   virtual BSTNode* MakeNewNode(int key) override {
      return new ExtendedRBTNode(key);
   }

   // Your code here

public:
   virtual int GetNthKey(int n) override {
      // Your code here (remove placeholder line below)
      return 0;
   }
};

#endif

自分で変更して試したソースコード

ExtendedRedBlackTree.h

#ifndef EXTENDEDREDBLACKTREE_H
#define EXTENDEDREDBLACKTREE_H

#include "RedBlackTree.h"
#include "ExtendedRBTNode.h"

class ExtendedRedBlackTree : public RedBlackTree {
protected:
   // Each node in an ExtendedRedBlackTree is an ExtendedRBTNode
   virtual BSTNode* MakeNewNode(int key) override {
      return new ExtendedRBTNode(key);
   }

   // Your code here
   //   Override the InsertNode function
   virtual void InsertNode(BSTNode* node) override {
       BinarySearchTree::InsertNode(node);
       node = (ExtendedRBTNode*)node->GetParent();
      
       while (node) {           
           
            RedBlackTree::InsertionBalance((ExtendedRBTNode*)node);
            static_cast<ExtendedRBTNode*>(node)->UpdateSubtreeKeyCount((ExtendedRBTNode*)node);
            node = (ExtendedRBTNode*)node->GetParent();
           
       }
   }


public:
   virtual int GetNthKey(int n) override {
      // Your code here (remove placeholder line below)
       int Index = 0;
       ExtendedRBTNode* current = static_cast<ExtendedRBTNode*>(GetRoot());
       while (current != nullptr) {
           int leftCount = current->GetLeft() == nullptr ? 0 : static_cast<ExtendedRBTNode*>(current->GetLeft())->GetSubtreeKeyCount();
           if (Index + leftCount == n) {
               return current->GetKey();
           }
           if (Index + leftCount < n) {
               Index += leftCount + 1;
               current = static_cast<ExtendedRBTNode*>(current->GetRight());
           }
           else {
               current = static_cast<ExtendedRBTNode*>(current->GetLeft());
           }
       }
       return -1;
   }
};

ExtendedRBTNode.h

#ifndef EXTENDEDRBTNODE_H
#define EXTENDEDRBTNODE_H

#include "RBTNode.h"

class ExtendedRBTNode : public RBTNode {
private:
   int subtreeKeyCount;

public:
   ExtendedRBTNode(int nodeKey) : RBTNode(nodeKey) {
      subtreeKeyCount = 1;
   }
   
   virtual int GetSubtreeKeyCount() override {
      return subtreeKeyCount;
   }
   
   // Your code here
   virtual void SetLeft(BSTNode* newLeftChild) override {
       RBTNode::SetLeft(newLeftChild);
       UpdateSubtreeKeyCount(newLeftChild);
   }

   virtual void SetRight(BSTNode* newRightChild) override {
       RBTNode::SetRight(newRightChild);
       UpdateSubtreeKeyCount(newRightChild);
   }

   virtual void UpdateSubtreeKeyCount(BSTNode* node) {
       int count = 1;

       if (GetLeft() != NULL) {
           count += ((ExtendedRBTNode*)GetLeft())->GetSubtreeKeyCount();
       }

       if (GetRight() != NULL) {
           count += ((ExtendedRBTNode*)GetRight())->GetSubtreeKeyCount();
       }

       subtreeKeyCount = count;
   }
};

#endif

発生している問題・エラーメッセージの一例

Inserting keys: 21, 64, 32, 91, 87, 66, 15, 88, 58, 20, 67, 82, 19, 44, 51
PASS: Inorder key verification
  Expected: { 15, 19, 20, 21, 32, 44, 51, 58, 64, 66, 67, 82, 87, 88, 91 }
  Actual:   { 15, 19, 20, 21, 32, 44, 51, 58, 64, 66, 67, 82, 87, 88, 91 }
FAIL: Node with key 15 has a subtree key count of 3, but the expected subtree key count is 2.
PASS: Node with key 19 has a subtree key count of 1
FAIL: Node with key 20 has a subtree key count of 2, but the expected subtree key count is 4.
FAIL: Node with key 21 has a subtree key count of 4, but the expected subtree key count is 1.
FAIL: Node with key 32 has a subtree key count of 9, but the expected subtree key count is 8.
FAIL: Node with key 44 has a subtree key count of 2, but the expected subtree key count is 1.
FAIL: Node with key 51 has a subtree key count of 1, but the expected subtree key count is 3.
FAIL: Node with key 58 has a subtree key count of 4, but the expected subtree key count is 1.
FAIL: Node with key 64 has a subtree key count of 1, but the expected subtree key count is 15.
FAIL: Node with key 66 has a subtree key count of 15, but the expected subtree key count is 1.
FAIL: Node with key 67 has a subtree key count of 2, but the expected subtree key count is 3.
PASS: Node with key 82 has a subtree key count of 1
FAIL: Node with key 87 has a subtree key count of 5, but the expected subtree key count is 6.
PASS: Node with key 88 has a subtree key count of 1
PASS: Node with key 91 has a subtree key count of 2

自分でも試してみましたが、エラーが起こって問題が解けません。わかる方がいましたら、変更を加えていただいたソースコード２つを送ってくださると幸いです。