## What is binary search tree iterator?

Binary Search Tree Iterator. Implement the BSTIterator class that represents an iterator over the in-order traversal of a binary search tree (BST): BSTIterator(TreeNode root) Initializes an object of the BSTIterator class. The root of the BST is given as part of the constructor.

## How do you use iterator in binary search tree?

Implement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST. Calling next() will return the next smallest number in the BST. Note: next() and hasNext() should run in average O(1) time and uses O(h) memory, where h is the height of the tree.

**How do you iterate through a tree?**

Here’s how it can be defined:

- First rule: The first node in the tree is the leftmost node in the tree.
- Next rule: The successor of a node is: Next-R rule: If it has a right subtree, the leftmost node in the right subtree. Next-U rule: Otherwise, traverse up the tree.

**What is an iterator object?**

In JavaScript an iterator is an object which defines a sequence and potentially a return value upon its termination. Specifically, an iterator is any object which implements the Iterator protocol by having a next() method that returns an object with two properties: value. The next value in the iteration sequence.

### How do you use an iterator in python?

Iterator in python is an object that is used to iterate over iterable objects like lists, tuples, dicts, and sets. The iterator object is initialized using the iter() method. It uses the next() method for iteration. next ( __next__ in Python 3) The next method returns the next value for the iterable.

### How do you iterate a tree without recursion?

1) Create an empty stack S. 2) Initialize current node as root 3) Push the current node to S and set current = current->left until current is NULL 4) If current is NULL and stack is not empty then a) Pop the top item from stack. b) Print the popped item, set current = popped_item->right c) Go to step 3.

**What are the 6 possible ways of traversing a binary tree?**

We can access these three elements in six different ways i.e. there are 6 possible permutations. These are also called DFS traversal of a tree: Pre-order: Root -> Left subtree -> Right subtree. Reverse Pre-order: Root -> Right subtree -> Left subtree.

**Why do we use iterator?**

Iterator in Java is used to traverse each and every element in the collection. Using it, traverse, obtain each element or you can even remove. ListIterator extends Iterator to allow bidirectional traversal of a list, and the modification of elements.

## How do you make an iterator?

An iterator can be created from an iterable by using the function iter(). Thus, when we pass this tuple to an iter() function, we will get an iterator. Actually, this is possible because the class of an object has a method __iter__, which returns an iterator.

## Why do we need iterator in Python?

Iterators allow lazy evaluation, only generating the next element of an iterable object when requested. This is useful for very large data sets. Iterators and generators can only be iterated over once. Generator Functions are better than Iterators.

**What is Morris tree traversal?**

Morris (InOrder) traversal is a tree traversal algorithm that does not employ the use of recursion or a stack. In this traversal, links are created as successors and nodes are printed using these links. Finally, the changes are reverted back to restore the original tree.

**How do I iterate over binary trees?**

If you make a right turn (i.e. this node was a left child),then that parent node is the successor

### How to create binary search tree using array?

Binary Tree Using Array. An array can be converted into a binary tree. 1) Parent : Parent of a node at index lies at (n-1)/2 except the root node. 2) Left Child : Left child of a node at index n lies at (2*n+1). 3) Right Child : Right child of a node at index n lies at (2*n+2). 4) Left Sibling : left Sibling of a node at index n lies at (n-1).

### How to search in a binary search tree?

Start from the root.

**Which is faster binary tree or binary search tree?**

The left and right sub-tree each must be a binary search tree. The binary search tree allows a faster search and deletion of items from the tree.Binary search tree also known as ordered or sorted binary tree. This is how a BST may look like with the data elements.