Uber Front end Developer Interview Questions and Answers

First round was a coding question with html, css, javascript to create 5 clickable boxes, change it's colors on click and update count

My mostly question were around node js frame works and other tools

Q1. Case study for the question asked
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Q2. Tell me something more about you
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Question are very tough and faad

Question like trees linked list and graphs

Round duration - 90 Minutes
Round difficulty - Easy

1 coding question which was quite easy. Some MCQ that includes basic questions related to html, css, javascript, oops, dbms and output.

Q1. 
LRU Cache Design Question
Design a data structure for a Least Recently Used (LRU) cache that supports the following operations:
1. get(key) - Return the value of the key if it exists in the cache; otherw...read more
Ans. 
Design a Least Recently Used (LRU) cache data structure that supports get and put operations with a given capacity.
• Implement a doubly linked list to keep track of the order of keys based on their recent usage.

• Use a hashmap to store key-value pairs for quick access and updates.

• When capacity is reached, evict the least recently used item before inserting a new one.

• Update the order of keys in the linked list whenever a ke
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Round duration - 90 Minutes
Round difficulty - Easy

easy round. Had some frontend questions related to html ,css, js , etc Explain Closures in JavaScript. In how many ways can we specify the CSS styles for the HTML element?

Q1. 
String Palindrome Verification
Given a string, your task is to determine if it is a palindrome considering only alphanumeric characters.
Input:
The input is a single string without any leading or trailing...read more
Ans. 
Check if a given string is a palindrome considering only alphanumeric characters.
• Remove non-alphanumeric characters from the input string.

• Compare the string with its reverse to check for palindrome.

• Handle edge cases like empty string or single character input.

• Use two pointers approach for efficient comparison.
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Q2. DBMS Questions
normalization, indexing
Ans. 
Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. Indexing is a technique to quickly retrieve data from a database.
• Normalization helps in reducing data redundancy by breaking down tables into smaller, related tables.

• Indexing is used to quickly retrieve data by creating indexes on columns in a table.

• Normalization ensures data integrity by minimizing data dupli...read more
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Round duration - 120 Minutes
Round difficulty - Hard

late at 8.00 pm

Q1. 
Priority CPU Scheduling Problem
Given 'N' processes with their “burst times”, where the “arrival time” for all processes is ‘0’, and the ‘priority’ of each process, your task is to compute the “waiting ti...read more
Ans. 
Implement Priority CPU Scheduling algorithm to compute waiting time and turn-around time for processes.
• Implement a function that takes in burst times, priorities, and number of processes as input

• Sort the processes based on priority, with lower process ID as tiebreaker

• Calculate waiting time and turn-around time for each process based on the scheduling algorithm
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Q2. Can you explain the concept of data spooling in operating systems?
Ans. 
Data spooling is a process where data is temporarily stored in a buffer before being sent to an output device.
• Data spooling helps in managing the flow of data between different devices by storing it temporarily.

• It allows for efficient processing of data by decoupling the input/output operations.

• Examples of data spooling include print spooling, where print jobs are stored in a queue before being sent to the printer.
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Q3. What is the difference between inheritance and generalization in the context of database management systems?
Ans. 
Inheritance is a relationship between a superclass and subclass, while generalization is a relationship between entities with common characteristics.
• Inheritance involves a parent-child relationship where the child class inherits attributes and methods from the parent class.

• Generalization involves grouping entities with common attributes into a higher-level entity.

• Inheritance is a specific form of generalization in obje...read more
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Coding a frontend UI from provided image. And creating a fucntional star rating system

Q1. Designing a Component API in React using Typescript.
Ans. 
Designing a Component API in React using Typescript involves defining props, state, and methods for the component.
• Define the props interface to specify the expected input data for the component

• Use typescript types to ensure type safety and prevent runtime errors

• Define the state interface to manage the internal state of the component

• Implement methods to handle user interactions and component logic

• Document the component
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Q2. Create a function that can clear all the timer ids at once.
Ans. 
Function to clear all timer ids at once
• Create an array to store all timer ids

• Iterate through the array and clear each timer id using clearTimeout() function
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Q1. Given a matrix zeros and ones find minimum distance for each one to a zero.
Ans. 
Given a matrix of zeros and ones, find the minimum distance for each one to a zero.
• Use breadth-first search (BFS) to find the minimum distance from each one to a zero.

• Start by initializing a queue with all the zeros in the matrix.

• While the queue is not empty, dequeue a zero and enqueue its neighboring ones.

• Keep track of the distance from each one to the nearest zero.

• Repeat until all ones have been visited.

• Return the ma
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30mins aptitude test

90 mins coding test for 3 questions

Q1. Why are you choosing this role
Ans. 
I am choosing this role because of my passion for creating user-friendly and visually appealing websites.
• Passion for front end development

• Enjoy creating user-friendly interfaces

• Excited about the creative aspect of web design
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Q2. Why should we write you
Ans. 
I am a dedicated and skilled front end developer with a passion for creating user-friendly interfaces.
• I have a strong understanding of HTML, CSS, and JavaScript

• I have experience with responsive design and cross-browser compatibility

• I am proficient in using front end frameworks like React and Angular
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Round duration - 60 minutes
Round difficulty - Easy

Round duration - 50 minutes
Round difficulty - Easy

Round duration - 60 minutes
Round difficulty - Easy

At the beginning of this round, the interviewer asked me about the data structures I knew. Linked lists, trees, graphs, arrays etc. was my answer. He asked me how well I knew Dynamic Programming. I said I wasn’t strong in that and he said that he would ask me a question on dynamic programming for sure.

Round duration - 40 minutes
Round difficulty - Easy

The interviewer asked me if I was comfortable with the interview process so far and how the previous interviews were. I said it was good and he gave me the first problem to solve.

Round duration - 60 minutes
Round difficulty - Easy

The interviewer asked me some Com­puter Sci­ence‍ fundamentals in this round as well as some behavioural questions.

Q1. Implement a Trie data structure and write functions to insert and search for a few words in it.
Ans. 
Implement a Trie data structure with insert and search functions.
• Create a TrieNode class with children and isEndOfWord attributes.

• Implement insert function to add words by iterating through characters.

• Implement search function to check if a word exists by traversing the Trie.

• Example: Insert 'apple', 'banana', 'orange' and search for 'apple' and 'grape'.
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