# How do you balance a binary tree?

## How do you balance a binary tree?

Very simply, a BST is defined by the following rule:

1. All nodes in the left subtree have key values less than or equal to the key value of the parent.
2. All nodes in the right subtree have key values greater than or equal to the key value of the parent.

What happens when a binary search tree is unbalanced?

Here’s the trouble with unbalanced trees: the moment that a binary tree becomes unbalanced, it loses its efficiency. Based on everything that we already know about binary search trees, we know that they are incredibly powerful because of their logarithmic runtime, which is exactly what makes them so fast and efficient.

Why is it problematic if a binary tree becomes unbalanced?

An extremely unbalanced tree, for example a tree where all nodes are linked to the left, means you still search through every single node before finding the last one, which is not the point of a tree at all and has no benefit over a linked list.

### Are binary trees always balanced?

Every complete binary tree is balanced but not the other way around. As implies, in a complete tree, always the level difference will be no more than 1 so it is always balanced.

What makes a tree balanced?

A tree is perfectly height-balanced if the left and right subtrees of any node are the same height. We will say that a tree is height-balanced if the heights of the left and right subtree’s of each node are within 1. The following tree fits this definition: We will say this tree is height-balanced.

How do you balance a binary tree in Python?

Approach to Solve this Problem

1. Take input of nodes of a Binary Tree.
2. Define a function to find the height of the tree.
3. A Boolean function to check recursively if the height difference of left subtree and right subtree is not more than ‘1’, then return True.
4. Return the Result.

## How do you balance a tree?

How to keep a tree in balance

1. First, Insert descends recursively down the tree until it finds a node n to append the new value.
2. If n is a leaf, adding a new child node increases the height of the subtree n by 1.
3. Insert now adds a new child node to node n .
4. The height increase is passed back to n ‘s parent node.

Why height balancing of the tree is required?

Height-balancing requirement. A node in a tree is height-balanced if the heights of its subtrees differ by no more than 1. The node holding 18 has a left subtree of height 0 and a right subtree of height 1. The root has two subtrees of height 2. Our goal is to keep our binary search trees height-balanced.

How do you know if a binary tree is balanced?

To check if a tree is height-balanced, get the height of left and right subtrees. Return true if difference between heights is not more than 1 and left and right subtrees are balanced, otherwise return false.

### What is a balanced binary tree example?

Height-balanced binary tree : is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. Example : Input : 1 / \ 2 3 Return : True or 1 Input 2 : 3 / 2 / 1 Return : False or 0 Because for the root node, left subtree has depth 2 and right subtree has depth 0.

How do you create a balanced BST?

Following is a simple algorithm where we first find the middle node of list and make it root of the tree to be constructed. 1) Get the Middle of the array and make it root. 2) Recursively do same for left half and right half. a) Get the middle of left half and make it left child of the root created in step 1.