Cohesity Member Technical Staff Interview Questions and Answers

A URL shortener is a tool that takes a long URL and creates a shorter, easier-to-share link.

• Generate a unique short code for each URL

• Store the short code and original URL in a database

• Redirect users from the short URL to the original URL

• Track clicks and analytics for each short URL

Design a thread-safe implementation of HashMap.

• Use synchronized methods or locks to ensure mutual exclusion.

• Consider using ConcurrentHashMap instead of HashMap.

• Use volatile keyword for variables accessed by multiple threads.

• Avoid using iterators as they may cause ConcurrentModificationException.

• Use atomic operations for read-modify-write operations.

• Consider using immutable keys to avoid synchronization issues.

I have worked on various projects involving software development, data analysis, and machine learning.

• Developed a web application for tracking personal fitness goals using React and Node.js

• Implemented a machine learning model to predict customer churn for a telecom company

• Analyzed data from a clinical trial to identify patterns in patient outcomes

Algorithm to find median in a stream of n numbers

• Sort the list and find the middle element for odd n

• For even n, find the average of middle two elements

• Use a min-heap and max-heap to maintain the smaller and larger half of the stream respectively

• Insert new elements into the appropriate heap and balance the heaps to ensure median is always at the top

Given 2 arrays, one with n elements and another with n-1 elements, answer the question.

• Compare the elements of both arrays to find the missing element.

• Use a loop or a built-in function to iterate through the arrays.

• Consider edge cases where the missing element is at the beginning or end of the array.

The question asks to link up all nodes present in the same level of a binary search tree using the next pointer.

• Traverse the tree level by level using a queue

• For each level, create a linked list by connecting the nodes using the next pointer

• Use a dummy node to keep track of the start of the linked list for each level

The question asks for the length of the longest absolute directory path string and how to optimize it.

• Use a depth-first search (DFS) algorithm to traverse the directory structure

• Maintain a stack to keep track of the current path length

• Keep updating the maximum path length encountered

• Consider the length of each directory/file name and the length of the path separators

Debugging a code of Dining Philosopher Problem

• Check for deadlock conditions

• Ensure that each philosopher can only pick up two forks at a time

• Implement a solution using semaphores or monitors

• Consider using a timeout mechanism to prevent deadlock

• Test the code with different scenarios to identify and fix any issues

Design a system to find the millionth person liking a particular comment.

• Use a database to store the likes for each comment

• Implement a counter to keep track of the number of likes for each comment

• Use a caching mechanism to improve performance

• Consider sharding or partitioning the data for scalability

• Implement a search algorithm to find the millionth person