Krenai Services Interview Questions and Answers

Q1. Explain selection sort.
Ans. 
Selection sort is a simple sorting algorithm that repeatedly selects the minimum element from an unsorted portion of the array and swaps it with the first unsorted element.
• Iterate through the array to find the smallest element.

• Swap the smallest element with the first unsorted element.

• Repeat the process for the remaining unsorted portion of the array.

• Time complexity is O(n^2) and space complexity is O(1).
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Q2. What are sql joins.
Ans. 
SQL joins are used to combine rows from two or more tables based on a related column between them.
• Joins are used to retrieve data from multiple tables in a single query.

• Types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.id = table2.id;
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Q3. What are procedures in sql.
Ans. 
Procedures in SQL are reusable blocks of code that perform a specific task.
• Procedures are stored in the database and can be called multiple times.

• They can accept input parameters and return output parameters.

• Procedures can contain SQL statements, control-of-flow statements, and error handling.

• Example: CREATE PROCEDURE GetEmployeeDetails AS SELECT * FROM Employees;

• Example: EXEC GetEmployeeDetails;
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Q4. Basics of core java.
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Q1. Wap to print pyramid star pattern.
Ans. 
Print a pyramid star pattern using nested loops.
• Use nested loops to print spaces and stars in each row

• Increment the number of stars in each row to form a pyramid shape
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Q2. Difference between == and .equals.
Ans. 
== is used for comparing reference equality, while .equals is used for comparing object equality in Java.
• == compares memory addresses of objects

• .equals compares the actual content of objects

• == is used for comparing primitive data types

• .equals is used for comparing objects in Java
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Q3. Explain quick sort.
Ans. 
Quick sort is a sorting algorithm that uses divide and conquer approach to sort an array efficiently.
• Divide the array into two sub-arrays based on a pivot element

• Recursively sort the sub-arrays

• Combine the sorted sub-arrays to get the final sorted array

• Example: [3, 6, 8, 10, 1, 2, 1] -> [1, 1, 2, 3, 6, 8, 10]
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Q4. Questions from collections like what is linked list etc
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Several sql question

Array question reverse

Q1. Several questions about project
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