Question

How do I insert an unsorted array into a Binary Search Tree as a Doubly Linked List in C++?

Answer 1

#include <iostream>

#include <cstdlib>

using namespace std;

class BinarySearchTree

{

private:

struct tree_node

{

tree_node* left;

tree_node* right;

int data;

};

tree_node* root;

public:

BinarySearchTree()

{

root = NULL;

}

bool isEmpty() const { return root == NULL; }

void print_inorder();

void inorder(tree_node*);

void insert(int);

};

// Smaller elements go left

// larger elements go right

void BinarySearchTree::insert(int d)

{

tree_node* t = new tree_node;

tree_node* parent;

t->data = d;

t->left = NULL;

t->right = NULL;

parent = NULL;

// is this a new tree?

if (isEmpty()) root = t;

else

{

//Note: ALL insertions are as leaf nodes

tree_node* curr;

curr = root;

// Find the Node's parent

while (curr)

{

parent = curr;

if (t->data > curr->data) curr = curr->right;

else curr = curr->left;

}

if (t->data < parent->data)

parent->left = t;

else

parent->right = t;

}

}

void BinarySearchTree::print_inorder()

{

inorder(root);

}

void BinarySearchTree::inorder(tree_node* p)

{

if (p != NULL)

{

if (p->left) inorder(p->left);

cout << " " << p->data << " ";

if (p->right) inorder(p->right);

}

else return;

}

int main()

{

BinarySearchTree b;

int arr[] = {10,4,3,6,1,2};

cout << " Insertion/Creation " << endl;

for(int i= 0 ; i<6;++i)

b.insert(arr[i]);

cout << " Insertion Done " << endl;

cout << " In-Order Traversal " << endl;

b.print_inorder();

}

===========================
See Output


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