# MOST COMMON Oracle CODING INTERVIEW QUESTIONS

###### The 15 Most Asked Questions in an Oracle Interview

Oracle is the second largest software company in the world. As a developer or software engineer, one of your goals must be to secure a job at one of the top software companies. __The interview process__ for these companies is no joke, and Oracle is no exception. Its interview questions are challenging.

In recent years, Oracle has expanded its focus on cloud computing and has begun offering various cloud-based services, including infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). With such ongoing inventions, Oracle must ensure that it hires the best talent.

But no need to worry about not making the cut. With the right skill and guidance, you can definitely get a job at Oracle. To guide you in this journey, we’ve created a brief blog to help you with Oracle interview questions. Have a good look at the information we share below, and you’ll surely ace your interview.

###### ARRAYS

Find the missing number in the array

Just like any other tech interview, you can expect arrays to come up in the Oracle interview questions. As a developer, you should know the importance of arrays. Arrays are one of the most f__undamental data structures__ in programming. And as a seasoned programmer, you are expected to have in-depth knowledge of arrays and a solid grasp on searching, sorting, and manipulating data. Arrays are widely used to represent and assess data effectively. And to measure your efficacy, the interviewer might throw questions like the following:

__Problem statement__

You are given an array containing ‘n’ distinct numbers taken from the range 0 to ‘n’. Since the array has only ‘n’ numbers out of the total ‘n+1’ numbers, find the missing number.

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Determine if the sum of two integers is equal to the given value

__Problem statement__

Given an array of integers and a value, determine if there are any two integers in the array whose sum is equal to the given value.

###### LINKED LISTS

Merge two sorted linked lists

Linked lists are one of the core concepts of computer science. You might face linked list queries at the beginning of your Oracle interview questions. Oracle interviewers might ask them in order to assess your knowledge of __Computer Science fundamentals__. They can ask different kinds of questions, so it’s better to refresh your memory and learn the different types and technical terms used in regard to linked lists. The questions can be related to the following:

Types of linked lists

Scenario questions

Differentiation questions

In-depth questions

The following are some examples of Oracle interview questions are:

__Problem statement__

Given two sorted linked lists, merge them so that the resulting linked list is also sorted.

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Copy linked list with arbitrary pointer

__Problem statement__

You are given a linked list where the node has two pointers. The first is the regular ‘next’ pointer. The second pointer is called ‘arbitrary_pointer’ and it can point to any node in the linked list.

Your job is to write code to make a deep copy of the given linked list. Here, deep copy means that any operations on the original list (inserting, modifying and removing) should not affect the copied list.

###### TREES

Level order traversal of a binary tree

Another common topic from Oracle interview questions involves your knowledge of trees. Trees are an important data structure that can help you solve complex problems and codes. The interviewer asks tree-related questions to assess your knowledge of hierarchical data. It also helps them evaluate your ability to design __algorithms__ and data structures.

These kinds of questions usually appear when you are applying for a Java developer or software engineer position. So, it is advised to review and practice your knowledge before appearing for the interview.

__Problem statement__

Given the root of a binary tree, display the node values at each level. Node values for all levels should be displayed on separate lines.

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Determine if a binary tree is a binary search tree

__Problem statement__

Given a Binary Tree, figure out whether it’s a Binary Search Tree. In a binary search tree, each node’s key value is smaller than the key value of all nodes in the right subtree, and are greater than the key values of all nodes in the left subtree i.e. L < N < R.

###### STRINGS

String segmentation

Oracle is well-known for its __database management system__, which handles a vast amount of text data. String-related questions can evaluate your understanding of text-processing concepts, such as text search algorithms. No matter if you're a new or an experienced developer, string questions are most likely going to be a part of your Oracle interview. Strings require algorithmic and problem-solving skills, so that’s why they are a part of Oracle interview questions.

__Problem statement__

Given a dictionary of words and an input string tell whether the input string can be completely segmented into dictionary words.

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Reverse words in a sentence

__Problem statement__

Given a string, find the length of the longest substring which has no repeating characters.

###### DYNAMIC PROGRAMMING

How many ways can you make change with coins and a total amount

The most important skill that Oracle or other top-rated companies look for in a programmer or software engineer is efficiency in finding the best solutions. Therefore, when we talk about efficacy and scalability, __dynamic programming__ can not be neglected in Oracle interview questions. Dynamic programming is used to solve and break down complex problems.

Most importantly, these questions require problem-solving skills, such as identifying optimal substructures, formulating recurrence relations, and implementing the solution using memoization or bottom-up approaches. And that is a skill only the best candidates will have.

Here is a quick question to analyze your dynamic programming skills.

__Problem statement__

Given coin denominations and total amount, find out the number of ways to make the change.

###### MATH AND STATS

Find Kth permutation

Math and statistics are important in coding interviews, especially for data scientists and software engineering positions. Math and stats questions assess quantitative reasoning abilities, problem-solving skills, as well as your understanding of algorithms and optimization and your familiarity with mathematical and statistical concepts relevant to data analysis and modeling.

So, it’s good to practice so that you can answer these types of Oracle interview questions.

__Problem Statement__

Given a set of ‘N’ elements, find the Kth permutation.

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Find all subsets of a given set of integers

__Problem statement__

You are given a set of integers and you have to find all the possible subsets of this set of integers.

###### BACKTRACKING

Print balanced brace combinations

Backtracking questions often involve making decisions based on certain constraints or conditions at each step. By asking backtracking questions, interviewers can assess your ability to design algorithms that make informed decisions, handle constraints, and identify optimal solutions based on specific requirements.

__Problem statement__

Print all braces combinations for a given value 'N' so that they are balanced.

###### GRAPHS

Clone a directed graph

Oracle deals with tough data and complex data models, and graph-related questions can assess your ability to effectively model and represent data using graphs. Moreover, graph-related questions can help companies evaluate their understanding of graph database concepts and query optimization. As we know, Oracle is known for its database management systems, so you can expect graphs in almost every Oracle coding interview.

__Problem statement__

Given the root node of a directed graph, clone this graph by creating its deep copy so that the cloned graph has the same vertices and edges as the original graph.

###### SORTING AND SEARCHING

Find the High/Low index

We all know that Oracle deals with vast amounts of data in database management systems, so it’s obvious that you will be asked about sorting and searching in your Oracle interview questions. Sorting and searching are fundamental operations when it comes to retrieving data efficiently. Most importantly, efficiently sorting and searching algorithms is crucial in improving software performance, especially when dealing with large datasets or time-sensitive operations.

__Problem Statement__

Given an array of points in the a 2D plane, find ‘K’ closest points to the origin.

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Search rotated array

__Problem statement__

Given an unsorted array of numbers, find the top ‘K’ frequently occurring numbers in it.

###### FINAL THOUGHTS

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Prepping for Oracle interview questions can be quite a challenge when you do not have the right path. However, we are here to help you with that. With the most experienced content architects and engineers on board, we’ve created this blog to help you with your Oracle interview. But if you need more guidance, you can always explore our__ interview prep courses__ for the best guidance and support.