Altimetrik Interview Questions and Answers

To identify whether a binary tree is a Binary Search Tree or not.

• Check if the left subtree is a Binary Search Tree

• Check if the right subtree is a Binary Search Tree

• Check if the root node is greater than all the nodes in the left subtree

• Check if the root node is less than all the nodes in the right subtree

Convert a BST to a binary tree with each element replaced by sum of all greater elements.

• Traverse the BST in reverse inorder and keep track of the sum of all greater elements.

• Replace each node's value with the sum and update the sum.

• Recursively perform the above steps on left and right subtrees.

• Time complexity: O(n), Space complexity: O(h) where h is the height of the tree.

Given an array, determine if it follows one of four patterns: increasing, decreasing, increase then decrease, or decrease then increase.

• Iterate through the array and compare each element to the previous one.

• If all elements are increasing, it follows the increasing pattern.

• If all elements are decreasing, it follows the decreasing pattern.

• If there is a point where the elements start decreasing after increasing, it follows the increase then decrease pattern.

• If there is a point w...read more

Solution for inorder traversal in sorted order without using array

• Implement a binary search tree and perform inorder traversal

• Use a stack to simulate the recursive function call stack

• Maintain a variable to keep track of the previously visited node

• Compare the current node with the previously visited node to check if it is in sorted order

Given an array of distinct positive numbers, find the maximum sum of non-adjacent elements.

• Use dynamic programming to keep track of the maximum sum at each index

• At each index, choose between including the current element or skipping it

• The maximum sum at index i is the maximum of the sum including i-2 and i or the sum excluding i

• Return the maximum sum at the last index

Find the 2nd highest salary from an employee table in SQL.

• Use the SELECT statement to retrieve the salaries in descending order.

• Use the LIMIT keyword to limit the result set to the second row.

• Use a subquery to exclude the highest salary from the result set.