Trell Senior Data Scientist Interview Questions and Answers

45 MCQ Which includes below topics
Basic core Java
Database
Spring
Hibernate
Angular
One program based on core Java logic

Q1. Sql, advance Excel formulas
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Q1. Explain Moving Average
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Moving Average is a statistical technique used to analyze data points by creating a series of averages of different subsets of the full data set.
• Moving Average helps in smoothing out fluctuations in data to identify trends over time.

• It is calculated by taking the average of a specific number of data points within a defined window.

• For example, a 3-day moving average for stock prices would be the average of the stock pri...read more
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Q2. Explain Decorators
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Decorators in Python are functions that modify the behavior of other functions.
• Decorators are denoted by the @ symbol followed by the decorator function name.

• They allow you to add functionality to an existing function without modifying its code.

• Common use cases include logging, timing, and authentication.

• Example: @decorator_function def function_to_decorate(): pass
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Q3. Explain Object Oriented Programming
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Object Oriented Programming is a programming paradigm based on the concept of objects, which can contain data and code.
• OOP focuses on creating objects that interact with each other to solve complex problems.

• Objects have attributes (data) and methods (functions) that can manipulate the data.

• Encapsulation, inheritance, and polymorphism are key principles of OOP.

• Example: In a car simulation program, a 'Car' object can hav...read more
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Q4. Explain classes objects
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Classes are blueprints for creating objects in object-oriented programming.
• Classes define the properties and behaviors of objects

• Objects are instances of classes

• Classes can inherit properties and behaviors from other classes

• Classes can have constructors to initialize objects

• Classes can have methods to perform actions
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Q5. Explain Functions
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Functions are blocks of code that perform a specific task and can be reused multiple times in a program.
• Functions help in organizing code and making it more modular.

• They can take input parameters and return output values.

• Functions can be called multiple times from different parts of the program.

• Examples: summing two numbers, finding the maximum value in a list.
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Q6. Pandas and Numpy
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Q7. Swap L1 and L5 in a list
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Swap L1 and L5 in a list
• Create a temporary variable to store the value of L1

• Assign the value of L5 to L1

• Assign the value of the temporary variable to L5
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Q1. Internal Working Of Hashmap, Java 8 features and two DSA questions one was based on the array and the second one was based on LinkedList. The first interview round was very excellent that's why they conduc...read more
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Q2. Detect loop in a LinkedList,
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Detect loop in a LinkedList
• Use two pointers, one moving at twice the speed of the other

• If there is a loop, the faster pointer will eventually catch up to the slower one

• If there is no loop, the faster pointer will reach the end of the list
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Q1. System Design HLD and LLD round which was the final round.
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Q2. HLD and LLD Designing round: Desing Architecture for ChatBot and Company Employee Data Management System.
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Q1. Basic js question closure, async defer and all
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Q2. Create autosuggest debounce, pollyfill
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Autosuggest debounce is a feature that delays the search suggestions until the user stops typing, and a polyfill is a piece of code that provides functionality that is not natively supported by the browser.
• Implement a debounce function to delay the autosuggest feature until the user stops typing.

• Use a polyfill to provide support for the autosuggest feature in browsers that do not natively support it.

• Example: Implement ...read more
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Q1. A programming question
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Q2. React-native architecture and flatlist
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Q3. Kadanes algorithm
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Kadane's algorithm is used to find the maximum subarray sum in an array of integers.
• Iterate through the array and keep track of the maximum sum ending at each index.

• At each index, choose between extending the previous subarray or starting a new subarray.

• Example: For array [-2, 1, -3, 4, -1, 2, 1, -5, 4], the maximum subarray sum is 6 (from index 3 to 6).
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Q4. Scalablity, performance
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Q1. Android activity lifecycle
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Q2. Android MVVM architecture
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