Algorithm Design Questions
A binary search tree (BST) is a data structure that organizes elements in a hierarchical manner. It is a binary tree where each node has at most two children, referred to as the left child and the right child. The BST follows a specific property: for any given node, all elements in its left subtree are smaller than the node, and all elements in its right subtree are greater than the node.
The operations performed on a binary search tree include:
1. Insertion: To insert an element into a BST, we compare the value of the element with the current node. If the value is smaller, we move to the left child; if it is greater, we move to the right child. We repeat this process until we find an empty spot to insert the new element.
2. Search: To search for an element in a BST, we start from the root node and compare the value with the current node. If the value is smaller, we move to the left child; if it is greater, we move to the right child. We continue this process until we find the desired element or reach a null node.
3. Deletion: To delete an element from a BST, we first search for the element. If the element is found, we consider three cases:
a) If the node to be deleted has no children, we simply remove it.
b) If the node to be deleted has one child, we replace the node with its child.
c) If the node to be deleted has two children, we find the minimum value in its right subtree (or the maximum value in its left subtree) and replace the node's value with it. Then, we recursively delete the duplicate value from the right subtree.
4. Traversal: There are three common ways to traverse a BST:
a) Inorder traversal: Visit the left subtree, then the current node, and finally the right subtree.
b) Preorder traversal: Visit the current node, then the left subtree, and finally the right subtree.
c) Postorder traversal: Visit the left subtree, then the right subtree, and finally the current node.
The binary search tree data structure provides efficient search, insertion, and deletion operations with an average time complexity of O(log n) for balanced trees. However, in the worst case scenario, when the tree is highly unbalanced, the time complexity can degrade to O(n).