Question

suppose you decide to change our binary Search Tree ADT to not allowing a duplicate element. how would you have to change the ADT specifications

Answer 1

#include <iostream>
#include <vector>
#include <sstream>
#include <queue>
using namespace std;

// Defines a structure to create a Node
struct Node
{
// Data member to store data
int data;
// Pointer to left child
Node *left;
// Pointer to right child
Node *right;
};// End of structure Node

// Class BST definition
class BST
{
// Creates an object of structure for root node
Node *root;
public:
// Default constructor
BST()
{
root = NULL;
}// End of default constructor

// Function to insert a node
void insert(int data)
{
// Create a new node
Node *newptr = new Node;
// Stores the data in node
newptr->data = data;
// Set the left and right pointer of the node to null
newptr->left = NULL;
newptr->right = NULL;

// Checks if root is null then it is the first node
if (root == NULL)
{
// Set the root to new node
root = newptr;
}// End of if condition
// Otherwise
else
{
// Create a temporary pointer of type node and point to root
Node *p = root;
// Create a parent pointer pointer of type node and assign null to it
Node *parent = NULL;
// Find the right location for the new node
// Loops till leaf node and node pointing to data is not equals to the inserted number
while ((p != NULL) && (p->data != data))
{
// Checks if the number to insert is less than current node data
if (data < p->data)
{
// Set the current node as parent
parent = p;
// Current node is pointing to its left
p = p->left;
}// End of if condition
// Otherwise number is greater than the current node data
else if (data > p -> data)
{
// Set the current node as parent
parent = p;
// Current node is pointing to its right
p = p->right;
}// End of else
else
cout<<"\n Duplicate element not allowed.";
}// End of while

// If the element is not in the BST
if (p == NULL)
{
// Checks if the number to insert is less than current node data
if (data < parent->data)
// Parent node left is pointing to new node
parent->left = newptr;
// Otherwise number is greater than the current node data
else if (data > parent->data)
// Parent node right is pointing to new node
parent->right = newptr;
else
cout<<"\n Duplicate element not allowed.";
}// End of if

// Otherwise node is already available
else
cout<<"\n Duplicate element not allowed."<<endl;
}// End of else
}// End of function

// Function for pre order traversal
void preOrderHelper(Node *p)
{
// Traverse: Root, Left, Right
// Checks if current node is not null
if (p != NULL)
{
// Displays the root node value
cout << p->data << " ";
// Moves towards left
preOrderHelper(p->left);
// Moves towards right
preOrderHelper(p->right);
}// End of if
}// End of function

// Function to call the function by passing root node to it
// For pre order traversal
void preOrder()
{
preOrderHelper(root);
}// End of function
};// End of class

// main function definition
int main()
{
// Creates a pointer of class BST
BST *t1 = new BST();

int n, num;

// Accepts number of elements require to insert
cout<<"\n Enter number of elements required to insert: ";
cin >> n;

// Loops till number of elements
for (int i = 0; i < n; i++)
{
// Accepts each element
cout<<"\n Enter the number to insert: ";
cin>>num;
// Calls the function to insert
t1->insert(num);
}// End of for loop
// Calls the function to display pre order
t1->preOrder();
return 0;
}// End of main function

Sample Output:

Enter number of elements required to insert: 6

Enter the number to insert: 10

Enter the number to insert: 22

Enter the number to insert: 33

Enter the number to insert: 10

Duplicate element not allowed.

Enter the number to insert: 55

Enter the number to insert: 66
10 22 33 55 66