CouponDunia Interview Questions, Process, and Tips

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

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

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.

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.

I am a software engineer with experience in developing web applications and a passion for problem-solving.

• Experienced in developing web applications using languages such as Java, Python, and JavaScript

• Proficient in using frameworks such as Spring, Django, and React

• Strong problem-solving skills and ability to work in a team environment

• Passionate about learning new technologies and keeping up with industry trends

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 follow...read more

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

Use machine learning algorithms to analyze user behavior and preferences to suggest personalized coupons.

• Collect user data such as purchase history, search history, and demographics

• Use machine learning algorithms to analyze the data and identify patterns

• Create personalized coupon suggestions based on the identified patterns

• Regularly update and refine the algorithm to improve accuracy

• Allow users to provide feedback on t

I am a highly motivated individual with a passion for learning and growth.

• I have a degree in computer science and have worked as a software developer for 3 years.

• I am proficient in several programming languages including Java, Python, and C++.

• I am a quick learner and enjoy taking on new challenges.

• In my free time, I enjoy hiking and playing guitar.

AJAX stands for Asynchronous JavaScript and XML. It is a technique used for creating fast and dynamic web pages.

• AJAX allows web pages to update asynchronously by exchanging small amounts of data with the server behind the scenes.

• It uses XMLHttpRequest object to communicate with the server.

• AJAX can be used to create interactive web applications that can update data without reloading the entire page.

• Examples of AJAX-base...read more

Print the Next Greater Element (NGE) for every element in an array. If it doesn’t exceed then print -1.

• Iterate through the array and for each element, find the next greater element using a stack.

• If the next greater element is found, print it. Otherwise, print -1.

• Time complexity: O(n)

AJAX is a technique for creating fast and dynamic web pages without reloading the entire page.

• AJAX stands for Asynchronous JavaScript and XML

• It allows for asynchronous communication between the client and server

• Data is sent and received in the background without interrupting the user's experience

• AJAX is commonly used for auto-suggest search boxes, real-time updates, and form submissions

• Examples of AJAX frameworks inclu

Find the minimum number of steps to reach a finish word from a start word by changing only one digit at a time.

• Use breadth-first search algorithm to find the shortest path.

• Create a graph with words as nodes and edges between words that differ by one character.

• Start from the start word and explore all its neighbors, then move to their neighbors and so on until the finish word is found.

• Keep track of visited nodes to avoi

Auto Complete system suggests possible search queries as the user types.

• Uses algorithms to predict and suggest search queries based on user input

• Saves time and effort for users by providing relevant suggestions

• Can be based on user history, location, and other factors

• Examples include Google search suggestion, YouTube search suggestion, and Amazon search suggestion

I am a highly motivated individual with a passion for learning and achieving my goals.

• I have a Bachelor's degree in Computer Science

• I have completed several internships in software development

• I am proficient in multiple programming languages including Java and Python

• I enjoy working in a team environment and collaborating with others to solve problems

• I am always looking for new challenges and opportunities to grow

Print the bottom view of a tree.

• Traverse the tree in level order and keep track of horizontal distance of each node from the root.

• Store the horizontal distance and node value in a map.

• Print the node values in the map for the minimum and maximum horizontal distance for each level.

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

• Traverse the BST in reverse order (right, root, left)

• Keep track of the sum of all greater elements seen so far

• Update the current node's value with the sum of all greater elements seen so far + its own value

• Recursively convert the right and left subtrees

Adding two numbers without arithmetic operators.

• Use bitwise operators like XOR, AND, and left shift.

• Add the two numbers using XOR and AND, then left shift the carry and add again until there is no carry.

• Example: 5 + 3 = 8. 5 in binary is 101, 3 in binary is 011. XOR gives 110, AND gives 001, left shift gives 010.

• Example continued: XOR 110 and 010 gives 100, AND 110 and 010 gives 010, left shift gives 1000. No carry, so

Use randomized pivot selection to avoid worst-case scenario

• Randomly select a pivot element instead of always choosing the first or last element

• This reduces the likelihood of selecting a pivot that is already in its correct position

• Example: Instead of always choosing the first element as pivot, randomly select an element between the first and last element

• This ensures that the worst-case scenario of O(n^2) is avoided and

Find length of longest string with no repeating characters.

• Use a hash set to keep track of seen characters.

• Iterate through the string and update the hash set and length.

• Return the maximum length found.

Minimum number of steps to reach finish word from start word in a dictionary with words of length 3 and changing only one digit.

• Use BFS algorithm to find the shortest path

• Create a graph with words as nodes and edges between words that differ by only one character

• Start BFS from the start word and stop when the finish word is found

• Return the length of the path from start to finish word

Finding pattern in an array of strings.

• Look for common prefixes or suffixes

• Check for repeating patterns

• Analyze the length of strings