Dell Senior Specialist Coder Interview Questions and Answers

Oops concepts in Java

• Encapsulation - hiding implementation details

• Inheritance - reusing code and creating parent-child relationships

• Polymorphism - multiple forms of a method or object

• Abstraction - creating abstract classes and interfaces

• Example: Encapsulation - using private variables and public methods

• Example: Inheritance - creating a subclass that inherits from a superclass

• Example: Polymorphism - using method overloa...read more

Altering columns in databases involves modifying the structure of a table by adding, deleting or modifying columns.

• Use ALTER TABLE statement to modify columns

• Add new columns using ADD COLUMN

• Delete columns using DROP COLUMN

• Modify columns using MODIFY COLUMN

• Changing column data type may result in data loss

Reversing a number in Java

• Convert the number to a string

• Use StringBuilder to reverse the string

• Convert the reversed string back to a number

To extract words from a line in Java, split the line using whitespace as delimiter.

• Use the split() method of String class

• Pass the whitespace regex as argument to split() method

• Iterate over the resulting array to get individual words

Find A-B of two sorted arrays A and B in O(m+n) time complexity.

• Create two pointers, one for each array, and compare the elements at those pointers.

• If the element in A is smaller, add it to the result array and move the A pointer forward.

• If the element in B is smaller, move the B pointer forward.

• Repeat until one of the pointers reaches the end of its array.

• Add any remaining elements in A to the result array.

• Time comple...read more

The routine should output the elements of the inorder traversal of a binary tree one by one in each call.

• Implement an inorder traversal algorithm recursively

• Use a global variable or pass a reference to keep track of the current element

• Call the routine repeatedly to get the next element in each call

Program to find minimum semesters required to complete courses with prerequisites

• Create a graph with courses as nodes and prerequisites as edges

• Use topological sorting to find the order of courses to be taken

• Calculate the minimum number of semesters based on the order obtained

• Handle cases where there are cycles in the graph