Binary Search Tree Iterator Using Stack | Using Log(N) Space | Leetcode 173 Solution in Hindi

Question Name:
Binary Search Tree Iterator using Stack

Question Statement:
1. Implement the BSTIterator class that represents an iterator over the in-order traversal of a binary search tree (BST):

2. BSTIterator(TreeNode root) Initializes an object of the BSTIterator class. The root of the BST is given as part of the constructor. The pointer should be initialized to a non-existent number smaller than any element in the BST.
boolean hasNext() Returns true if there exists a number in the traversal to the right of the pointer, otherwise returns false.
int next() Moves the pointer to the right, then returns the number at the pointer.
Notice that by initializing the pointer to a non-existent smallest number, the first call to next() will return the smallest element in the BST.
3. You may assume that next() calls will always be valid. That is, there will be at least a next number in the in-order traversal when next() is called.

Topic: #Tree #BinaryTree #BinarySearchTree #BST #Iterator #BSTItertor

Used #DataStructure: #Stack #LinkedList

#TimeComplexity: O(N)

#SpaceComplexity: O(Log(N)), worst case : O(N)

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Linked Question:

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Smimilar Questions:

1. InOrder Morris Traversal In BinaryTree:

b. Youtube Link:

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#Tree, #BinaryTree, #BinarySearchTree, #BST, #geeksFoeGeeks, #leetcode, #BT, #InOrderMorrisTraversal, #MorrisTraversal #Morris,
#BSTIterator, #BST, #BSTInO1Space, #bstiterator

[shivammehta]

Awesome making videos....That way of using likedlist as a stack was new to me and I found it really

[rishabhgoyal]

We could have also used Iterative Inorder taught by Smeet Malik Sir.

[ManishSharma-fivr]

Thank You for your efforts. You explained it very well.

[ayushkhandelwal]

Great explanation sir... Thank you for your efforts 🙏

[ramaselvam]

Suggestion: If you make videos in english it will be helpfull for many learners across the world.

[garimakumari]

thanku thanku thanku so much for provising this content

[AnkitSingh-xpmm]

The last few seconds where you stated that morris traversal is better than this iterative approach, gave me such relief.

I was doubting my understanding of morris's traversal throughout 30minutes because I thought morris should be definitely better than this.

Suggestions: You can mention better approaches in the beginning.
Anyways, great explanation, really appreciate your patience while explaining.