PayPal Front end Developer Interview Questions and Answers

Q1. Closures, setTimeout, Eventloop in javascript
Add your answer
Q2. How to center a div in css3
Ans. 
To center a div in CSS3, use the 'margin: auto;' property along with a set width.
• Set the width of the div

• Use 'margin: auto;' to center the div horizontally

• Make sure the parent container has a defined width
Answered by AI
Add your answer
Q3. Call , bind and apply functions in javascript
Ans. 
call, bind, and apply are methods used to manipulate the context of a function in JavaScript.
• call() is used to invoke a function with a specified 'this' value and arguments provided individually.

• bind() is used to create a new function with a specified 'this' value and initial arguments.

• apply() is used to invoke a function with a specified 'this' value and arguments provided as an array.
Answered by AI
Add your answer

It was on hackerrank, it was given to solve 3 questions in JS along with quiz on js concepts

It was a js fundamental round, was asked similar JS problems asked in the hackerrank test

Q1. Describe your favourite/last project
Ans. 
Developed a responsive e-commerce website for a local boutique selling handmade jewelry
• Used HTML, CSS, and JavaScript to create a visually appealing and user-friendly interface

• Implemented a product carousel to showcase different jewelry collections

• Integrated a payment gateway for secure online transactions
Answered by AI
Add your answer
Q2. How to keep your updated in tech
Ans. 
Stay updated by regularly reading tech blogs, attending conferences, taking online courses, and networking with other professionals.
• Read tech blogs regularly (e.g. TechCrunch, Mashable)

• Attend tech conferences and workshops

• Take online courses and tutorials (e.g. Udemy, Coursera)

• Network with other professionals in the field (e.g. LinkedIn, Meetup)
Answered by AI
Add your answer
Q3. Do you try every new framework comes in the market
Ans. 
I do not try every new framework that comes in the market, but I do stay updated on the latest trends and evaluate them based on project requirements.
• I prioritize learning frameworks that align with the project needs

• I assess the pros and cons of new frameworks before deciding to use them

• I stay updated on industry trends and experiment with new frameworks in personal projects
Answered by AI
Add your answer
Q4. How will you optimise a code
Ans. 
Optimizing code involves identifying and fixing bottlenecks to improve performance and efficiency.
• Identify and remove unnecessary code or functions

• Use efficient algorithms and data structures

• Minimize network requests and optimize asset loading

• Implement caching mechanisms

• Profile and analyze code performance
Answered by AI
Add your answer

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
Answered by AI
Add your answer

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.
Answered by AI
Add your answer
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
Answered by AI
Add your answer

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
Answered by AI
Add your answer
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.
Answered by AI
Add your answer
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
Answered by AI
Add your answer

Round duration - 90 minutes
Round difficulty - Medium

3 coding Questions:
1st : Easy question based on simple loop iteration
2nd :Medium level Dp question 
3rd : Medium level tree question(where we were not just required to complete the tree function but to build whole bst from 
scratch) 

It was conducted from 1:30 - 3:00 pm.
The coding platform was very good (as auto indentation and auto completion of brackets were there)
having camera on.

Q1. 
Selling Stock Problem Statement
You are given the stock prices for N days. Each day i signifies the price of a stock on that day. Your goal is to calculate the maximum profit that can be achieved by buyin...read more
Ans. 
Calculate maximum profit by buying and selling stocks on different days.
• Iterate through the stock prices and buy on the day when the price is lower than the next day's price, and sell on the day when the price is higher than the next day's price.

• Keep track of the total profit earned by summing up the differences between buying and selling prices.

• Return the total profit as the maximum profit that can be earned.
Answered by AI
Add your answer
Q2. 
Minimum Time to Burn a Binary Tree from a Leaf Node
You are given a binary tree with 'N' unique nodes, and a specific start node from where the fire will begin. The task is to determine the time in minute...read more
Ans. 
The task is to determine the time in minutes required to burn the entire binary tree starting from a given node.
• Traverse the tree from the given start node to calculate the time taken to burn the entire tree.

• Use a queue to keep track of nodes and their burning time.

• Increment the burning time for each level of nodes until the entire tree is burned.
Answered by AI
Add your answer

Round duration - 75-80 minutes
Round difficulty - Hard

This was a completely technical coding round where I was asked to solve the problems of data structures.
The codepad where i was asked to code was fine,
The interviewer was very friendly and was helpful and understanding.
I also asked him about his work and experience in the company and some other questions.

Q1. 
Matrix Maximum Path Sum Problem
Given an N*M matrix filled with integer numbers, your task is to find the maximum path sum starting from any cell in the first row and ending at any cell in the last row. Y...read more
Add your answer

Round duration - 45 minutes
Round difficulty - Easy

It was held on Gmeet platform
The interviewer was very experienced person and was very nice too.
He made me comfortable by first introducing himself in a very detailed way and then asking me mine introduction
Since I feel that his internet connection was not very good so he turned off his camera but I decided not to turn off mine as in online interviews your face reviles your confidence 
the interviewer mostly asked me questions about my interests in technical field and the project that I have done

Round duration - 70 minutes
Round difficulty - Medium

Timing: 6:00 pm
3 coding questions of medium to be solved in 70 minutes.

Q1. 
Maximum Subarray Sum Problem Statement
Given an array of numbers, the task is to find the maximum sum of any contiguous subarray of the array.
Input:
The first line of input contains the size of the arr...read more
Ans. 
Find the maximum sum of any contiguous subarray in an array of numbers in O(N) time.
• Use Kadane's algorithm to find the maximum subarray sum in O(N) time.

• Initialize two variables: maxEndingHere and maxSoFar to keep track of the maximum sum.

• Iterate through the array and update the variables accordingly.

• Return the maxSoFar as the result.
Answered by AI
Add your answer
Q2. 
Closest Leaf in a Binary Tree
Ninja is stuck in a maze represented as a binary tree, and he is at a specific node ‘X’. Help Ninja find the shortest path to the nearest leaf node, which is considered an ex...read more
Ans. 
Find the minimum distance from a given node to the nearest leaf node in a binary tree.
• Traverse the binary tree from the given node 'X' to find the nearest leaf node.

• Use a queue for level order traversal to efficiently find the nearest leaf node.

• Calculate the distance from node 'X' to each leaf node and return the minimum distance.
Answered by AI
Add your answer
Q3. 
Rotting Oranges Problem Statement
You are given a grid containing oranges where each cell of the grid can contain one of the three integer values:
• 0 - representing an empty cell
• 1 - representing a fre...read more
Ans. 
Find the minimum time required to rot all fresh oranges in a grid.
• Use Breadth First Search (BFS) to simulate the rotting process of oranges.

• Track the time taken to rot all fresh oranges and return the result.

• If any fresh oranges remain after simulation, return -1 as it is impossible to rot all oranges.
Answered by AI
Add your answer

Round duration - 45 minutes
Round difficulty - Medium

Timing: 2:00 pm
Online round over google meet, code at google docs.
The interviewer was friendly, encouraging, and humble.

Q1. 
Smallest Integer Not Representable as Subset Sum
Given a non-decreasing sorted array ARR of N positive numbers, determine the smallest positive integer that cannot be expressed as the sum of elements from...read more
Ans. 
The task is to find the smallest positive integer value that cannot be represented as a sum of elements of any proper subset of the given array.
• The array is sorted in non-decreasing order, so we can iterate through the array and keep track of the maximum sum we can form.

• If the current element is greater than the maximum sum + 1, then the maximum sum + 1 is the smallest positive integer that cannot be represented.

• If all...read more
Answered by AI
Add your answer

Round duration - 45 minutes
Round difficulty - Medium

Timing: 2:00 pm
Online round over google meet, code at google docs.
The interviewer was not speaking much. It was a bit strange.

Q1. 
Bottom Right View of Binary Tree Problem Statement
Your task is to identify and return the bottom right view of a given binary tree.
This involves viewing the binary tree from an angle of 45 degrees from...read more
Ans. 
Identify and return the bottom right view of a given binary tree by viewing it from an angle of 45 degrees from the bottom right side.
• Traverse the binary tree in a right-to-left manner and keep track of the last node encountered at each level.

• Use a queue for level order traversal and update the result array with the last node at each level.

• Return the result array sorted in ascending order as the bottom right view of th
Answered by AI
Add your answer

Round duration - 30 Minutes
Round difficulty - Easy

Timing: 7:00 pm
The interviewer was friendly and in a bit of a hurry.