Balance a Binary Search Tree

In this video, we will discuss how to balance an unbalanced Binary Search Tree (BST) into a balanced one with minimal height. The key idea is to perform an in-order traversal of the BST, which will give us the elements in sorted order. With this sorted array of elements, we can then recursively construct a balanced BST by selecting the middle element as the root, and the left and right subtrees are formed by the elements to the left and right of the middle element.

We begin by traversing the BST in in-order to store the elements in a sorted array. Once we have the sorted array, we recursively build the balanced BST by choosing the middle element as the root of the subtree and then applying the same process to the left and right portions of the array. This method runs in O(n) time, where n is the number of nodes in the tree, because we perform two passes: one for the in-order traversal and another for building the balanced tree. The auxiliary space used is O(n) to store the nodes of the BST during the traversal and construction. Watch the video for a step-by-step breakdown of the process and its implementation.

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