CleverTap Back End Engineer Interview Questions and Answers

Q1. Describe Life cycle in react
Ans. 
React has three main phases in its lifecycle: mounting, updating, and unmounting.
• Mounting: when a component is created and inserted into the DOM

• Updating: when a component is updated due to changes in props or state

• Unmounting: when a component is removed from the DOM

• Lifecycle methods can be used to perform actions at each phase, such as componentDidMount() or componentWillUnmount()

• React also has error handling methods,
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Q2. Explain strict mode in javascript and it's use
Ans. 
Strict mode is a way to write secure and optimized JavaScript code.
• Enables catching of silent errors

• Disallows duplicate property names or parameters

• Prevents use of undeclared variables

• Makes `eval()` safer to use

• Throws errors on invalid usage of `this` keyword
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CURD operations along with implementation of a mock UI

Q1. Medium prepare well on data structure
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Q2. Find duplicate elements in array
Ans. 
Find duplicate elements in array
• Iterate through array and compare each element with all other elements

• Use a hash table to keep track of seen elements

• Sort the array and compare adjacent elements
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Q3. Remove duplicate elements in array
Ans. 
Remove duplicate elements in array
• Use a hash table to keep track of elements already seen

• Sort the array and remove adjacent duplicates

• Use a Set to store unique elements
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Q1. Based on api fetching and data optimazation
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Q1. Basic hr questions like inmovation creation difference
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Q1. With manager one to one discussion on projects
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Q1. What is jenkins pipeline
Ans. 
Jenkins pipeline is a suite of plugins that supports implementing and integrating continuous delivery pipelines.
• Jenkins pipeline allows defining a series of steps to be executed in a specific order.

• It can be written in a Jenkinsfile which is checked into source control.

• Pipeline stages can include building, testing, and deploying code.

• Pipeline scripts can be written in Groovy language.
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Q2. What is shared library in jenkins
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Shared libraries in Jenkins are reusable code libraries that can be used across multiple Jenkins pipelines.
• Shared libraries allow you to define common functions and classes that can be used in multiple Jenkins pipelines

• They help in reducing duplication of code and promoting code reusability

• Shared libraries are stored in source control repositories and can be versioned for better management

• They are typically written in ...read more
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Create an API using Notepad to check if a string is a palindrome or not.

Q1. Solid principal
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Q1. Basics Oops concepts and SQL queries along with currently working projects stacks
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Q1. More in-depth technical questions use of reflections etc
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Q1. Usual HR interviews company values etc
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SQL code development

2 Leetcode medium - LRU Cache and sliding window question

Q1. Design Whatsapp
Ans. 
Design a messaging app like Whatsapp
• Implement end-to-end encryption for secure messaging

• Allow users to send text messages, images, videos, and documents

• Include features like group chats, voice and video calls, status updates

• Provide option for users to share their location

• Develop a user-friendly interface with customizable settings
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