10+ iEnergizer Interview Questions and Answers

Calculate total score based on guessing colors in a slot machine.

• Iterate through each slot in the original and guess strings to compare colors.

• Count perfect hits when color matches in correct slot, and pseudo-hits when color matches in different slot.

• Calculate total score by adding perfect hits and pseudo-hits.

• Handle edge cases like invalid input strings or exceeding constraints.

This interview question covers various topics in Java programming, including OOP concepts, inheritance, keywords, and implementing mathematical algorithms.

• OOP concepts include encapsulation, inheritance, polymorphism, and abstraction.

• Inheritance allows a class to inherit properties and methods from another class.

• To prevent inheritance in Java, use the 'final' keyword before the class declaration.

• Sealed, final, and static are keywords in Java with different functionalities.

• Imp...read more

Rotate an array left by a specified number of elements for each query.

• Parse input: read number of test cases, array size, queries, and array elements

• For each query, left rotate the array by the specified number of elements

• Return the modified array for each query

Given an array and a target sum, find pairs of elements that add up to the target sum.

• Iterate through the array and for each element, check if the complement (target sum - current element) exists in a hash set.

• If the complement exists, add the pair to the result list.

• Sort the result list based on the first element of each pair, and then the second element if the first elements are equal.

The N Queens Problem involves finding all possible placements of N queens on an N x N chessboard where no two queens threaten each other.

• Understand the constraints of the problem: N represents the size of the chessboard and the number of queens, and queens can attack each other if they are in the same row, column, or diagonal.

• Implement a backtracking algorithm to explore all possible configurations of queen placements without conflicts.

• Ensure that each valid configuration is ...read more

Answers to interview questions for Software Engineer Trainee

• Primary foreign key is a column in a table that is used to link to the primary key of another table

• ACID properties are Atomicity, Consistency, Isolation, and Durability which ensure database transactions are reliable

• To return 3rd maximum salary, use the LIMIT and OFFSET clauses in SQL

• SQL join is used to combine data from two or more tables based on a related column

• IN in SQL is used to specify multiple values in a WHE...read more

Implement Fibonacci using dynamic programming and discuss strengths and weaknesses.

• Dynamic programming uses memoization to store previously calculated values

• Fibonacci sequence is a classic example of dynamic programming

• Strengths: efficient, reduces redundant calculations, improves performance

• Weaknesses: requires additional memory, may not be suitable for small problems

• Example: fib(n) = fib(n-1) + fib(n-2), with base cases fib(0) = 0 and fib(1) = 1

OOPS Concepts are fundamental principles of Object-Oriented Programming.

• Encapsulation - bundling of data and methods that operate on that data

• Inheritance - ability of a class to inherit properties and methods from its parent class

• Polymorphism - ability of objects to take on multiple forms

• Abstraction - hiding of complex implementation details from the user

• Example code: class Car { private String make; public void setMake(String make) { this.make = make; } }

Program to add a node to the end of a linked list

• Create a new node with the data to be added

• Traverse the linked list to reach the last node

• Update the next pointer of the last node to point to the new node

Program to check if a number is palindrome or not.

• Convert the number to a string for easier comparison

• Reverse the string and compare it with the original string

• If they are the same, the number is a palindrome

Double linked lists are used when there is a need to traverse the list in both directions efficiently.

• Allows for traversal in both directions

• Insertions and deletions can be done in constant time

• Used in implementations of undo functionality in text editors

Inheritance allows a class to inherit properties and methods from another class, while polymorphism allows objects of different classes to be treated as objects of a common superclass.

• Create a base class with common properties and methods

• Create derived classes that inherit from the base class and add their own unique properties and methods

• Use virtual functions in the base class and override them in the derived classes to achieve polymorphism

Code to reverse a given string.

• Iterate through the string from end to start and append each character to a new string.

• Use built-in functions like reverse() in Python or StringBuilder.reverse() in Java.

• Convert the string to an array, reverse the array, and then convert it back to a string.

Reverse a linked list

• Iterate through the linked list and reverse the pointers

• Use three pointers to keep track of current, previous, and next nodes

• Update the next pointer of each node to point to the previous node