Oracle
600+ Interview Questions and Answers
You are given an array/list ARR consisting of N integers. Your task is to find all the distinct triplets present in the array which adds up to a given number K.
An array is said to have a...read more
Given a number N, find its square root. You need to find and print only the integral part of square root of N.
For eg. if number given is 18, answer is 4.
Input format :
Integer N Output ...read more
You are given an array, ‘COORDINATES’ that represents the integer coordinates of some points on a 2D plane. Your task is to find the minimum cost to make all the points connect...read more
You have been given a singly Linked List of 'N' nodes with integer data and an integer 'K'. Your task is to remove the Kth node from the end of the given Linked List.
For example:
The gi...read moreYou have been given an integer array/list 'ARR' of size 'N'. Your task is to return the total number of those subsequences of the array in which all the elements are equal.
A subsequence of a ...read more
You are given an array 'ARR' of 'N' positive integers. Your task is to find if we can partition the given array into two subsets such that the sum of elements in both subsets is equal....read more
You are given a string of length N. You need to reverse the string word by word. There can be multiple spaces between two words and there can be leading or trailing spaces but in the ou...read more
For a given integer array/list 'ARR' of size 'N', find the total number of 'Inversions' that may exist.
An inversion is defined for a pair of integers in the array/list when the following two co...read more
Q9. Puzzle: – Two persons X and Y are sitting side by side with a coin in each’s hand. The game is to simultaneously flip the coin till anyone wins. Player X will win if he gets a consecutive HEAD, TAIL however Y w...
read moreThe game is not fair.
Player X has a higher chance of winning as they only need to get a consecutive HEAD, TAIL.
Player Y needs to get a consecutive HEAD, HEAD which is less likely to occur.
The probability of Player X winning is higher than Player Y winning.
You are given an N * N matrix of integers where each row and each column is sorted in increasing order. You are given a target integer 'X'. Find the position of...read more
You're given string ‘STR’ consisting solely of “{“, “}”, “(“, “)”, “[“ and “]” . Determine whether the parentheses are balanced.
Input Format:
The first line contains an Integer 'T' which denot...read moreA lady has 10 bags full of coins. Each bag contains 1000 coins. But one bag is full of forgeries, and she just can’t recall which one. She does know that genuine coins weigh 1 gram, but forgeries weigh 1....read more
You are given a matrix ‘MAT’. Print the transpose of the matrix. The transpose of a matrix is obtained by changing rows to columns and columns to rows. In other words, transpose of a matrix...read more
You are given the arrival and departure times of N trains at a railway station in a day. You need to find the minimum of platforms required for the railway station such that no ...read more
You are given a positive number ‘N.’ You need to find all the numbers such that the sum of digits of those numbers to the number itself is equal to ‘N.’
For example:
You are given ‘N’ as 21, th...read moreQ16. In a bag you have 20 black balls and 16 red balls.When you take out 2 black balls you take another white ball.If you take 2 white balls then you take out 1 black ball and if balls are of different color you tak...
read moreThe last ball that will be left is black.
When you take out 2 black balls, you take another white ball.
If you take 2 white balls, you take out 1 black ball.
If balls are of different color, you take out another black ball.
Since there are more black balls initially, the last ball will be black.
You are given a string ‘S’. Your task is to return all distinct palindromic substrings of the given string in alphabetical order.
A string is said to be palindrome if the reverse of the st...read more
You are given two sorted linked lists. You have to merge them to produce a combined sorted linked list. You need to return the head of the final linked list.
Note:
The given linked ...read moreGiven the head node of the singly linked list, return a pointer pointing to the middle of the linked list.
If there are an odd number of elements, return the middle element if there are eve...read more
You are given two numbers, ‘X’ and ‘Y’. Your task is to find the greatest common divisor of the given two numbers.
The Greatest Common Divisor of any two integers is the largest number th...read more
You have been given a Binary Tree of distinct integers and two nodes ‘X’ and ‘Y’. You are supposed to return the LCA (Lowest Common Ancestor) of ‘X’ and ‘Y’.
The LCA of ‘X’ and ‘Y’ in the bina...read more
You are given an array ‘ARR’ consisting of 'N' integers, and your task is to sort the given array in non-decreasing order using the Heap sort algorithm.
Input Format:
The first line of the input contai...read moreYou are given a 'M' x 'N' matrix of characters, 'CHARACTER_MATRIX' and a string 'WORD'. Your task is to find and print all occurrences of the string in the given character matrix. You are al...read more
You are given an array 'nums' consisting of first N positive integers. But from the N integers, one of the integers occurs twice in the array, and one of the integers is mis...read more
Given an array ‘pre[]’ of ‘n’ elements that represent Preorder traversal of a spacial binary tree where every node has either 0 or 2 children. Also Given a boolean array ‘i...read more
1. He asked me to write an SQL query, “Given a table with duplicate rows, remove duplicate rows from table”. I was not able to solve this question.
2. He asked me to write an SQL query, “Given empl...read more
Pre-requisites: Anagrams are defined as words or names that can be formed by rearranging letters of another word. Such as "spar" can be formed by rearranging letters of "rasp". Hence, "spar" and "r...read more
You are given a string EXP which is a valid infix expression. Convert the given infix expression to postfix expression.
Infix expression is of the form a op b. Where operator is is between the o...read more
You have been given an array/list 'ARR' of integers. Your task is to find the second largest element present in the 'ARR'.
Note:
a) Duplicate elements may be present. b) If no...read moreYou are given an array consisting of 0s and 1s. You need to find the length of the largest subarray with an equal number of 0s and 1s.
For example:
If the given ar...read moreYou are given an array of integers 'ARR' of length 'N' and an integer Target. Your task is to return all pairs of elements such that they add up to Target.
Note:
We cannot use the element at a given inde...read moreQ32. Design a website similar to bookmyshow.com for booking cinema tickets but it must be for a single location only which can have multiple theatres in it. In this he wanted me to design a basic rough GUI, relevant...
read moreDesign a website similar to bookmyshow.com for booking cinema tickets for a single location with multiple theatres.
Design a user-friendly GUI with options for advance booking, user login, user registration, movie rating, and saving card details.
Create relevant database tables to store information about movies, theatres, bookings, user details, and card details.
Link the GUI to the database to enable data flow and retrieval.
Implement features like advance booking, where users c...read more
You are given two Strings 'P' and 'Q' of equal length. Your task is to check whether String 'P' can be converted into String 'Q' by cyclically rotating it to t...read more
Q34. 1. Write a program to remove duplicate elements from String and mention the count of duplication.
Program to remove duplicate elements from String and count their occurrences.
Create a HashSet to store unique characters from the String.
Iterate through the String and add each character to the HashSet.
While adding, check if the character already exists in the HashSet and increment its count.
Print the count of each character that has duplicates.
Return the modified String with duplicates removed.
You have been given ‘K’ different arrays/lists, which are sorted individually (in ascending order). You need to merge all the given arrays/list such that the output array/list should be sor...read more
Given a string “STR”, you need to remove spaces from the string “STR” and rewrite in the Pascal case. Your task is to return the string “STR”.
In the Pascal case writing style we ...read more
Q37. Tell me about the OS your phone uses? What are the other phone operating systems available in the market
My phone uses iOS. Other phone operating systems available in the market are Android, Windows, and Blackberry OS.
iOS is developed by Apple and is exclusive to iPhones and iPads.
Android is developed by Google and is used by various phone manufacturers such as Samsung, LG, and HTC.
Windows is developed by Microsoft and is used by Nokia and other phone manufacturers.
Blackberry OS is developed by Blackberry and is exclusive to Blackberry phones.
You have been given an array 'PRICES' consisting of 'N' integers where PRICES[i] denotes the price of a given stock on the i-th day. You are also given an integer 'K' denoting the...read more
Q39. Provided a string a character and a count, you have to print the string after the specified character has occurred count number of times. Ex: String: “This is demo string” Character: ‘i’ Count: 3 Output: “ng” H...
read moreThe program prints the substring after a specified character has occurred a certain number of times in a given string.
Iterate through the string to find the specified character.
Keep track of the count of occurrences of the character.
Once the count reaches the specified count, extract the substring after that position.
Handle corner cases such as when the character is not in the string or when it doesn't occur the specified number of times.
Ninja loves playing with numbers. One day Alice gives him some numbers and asks him to find the Kth largest value among them.
Input Format:
The first line of input contains an integer ‘T,’ de...read moreYou're given string ‘STR’ consisting solely of “{“, “}”, “(“, “)”, “[“ and “]” . Determine whether the parentheses are balanced.
Input Format:
The first line contains an Integer 'T' which denot...read moreQ42. There N rooms in a hotel so customers will check-in and check-out a rooms simultaneously so which type of data structure you implement and it should be efficient and extension of this prebooking will also happe...
read moreTo efficiently manage room bookings and prebookings in a hotel, a priority queue data structure can be implemented.
A priority queue can be used to prioritize room bookings based on check-in dates.
When a customer checks out, the room becomes available and can be assigned to the next customer in the priority queue.
Prebookings can be stored separately and checked against the availability of rooms before assigning them to customers.
The priority queue can be implemented using a bi...read more
You are given a 2-dimensional array/list having N rows and M columns, which is filled with ones(1) and zeroes(0). 1 signifies land, and 0 signifies water.
A cell is said to be connected to...read more
Given a string ‘str’ and a string ‘pat’. The string s has some wildcard characters i.e ‘?’ and ‘*’.
If any character is a ‘?’ we can replace that character with any other character. If a...read moreGiven a singly linked list, you have to detect the loop and remove the loop from the linked list, if present. You have to make changes in the given linked list itself and return the update...read more
Given a binary tree having a positive integer written on each of its nodes. Your task is to find the vertical sum of node values i.e. the sum of nodes that can be connected by a ver...read more
You have been given an array/list 'PREORDER' representing the preorder traversal of a BST with 'N' nodes. All the elements in the given array have distinct values.
Your task is to const...read more
For a given binary tree, convert it to its sum tree. That is, replace every node data with sum of its immediate children, keeping leaf nodes 0. Finally, return its preorder.
For example:
The input for t...read moreGiven an array ARR of N integers and an integer S. The task is to find whether there exists a subarray(positive length) of the given array such that the sum of elements of the subarray eq...read more
You are given a square matrix of non-negative integers of size 'N x N'. Your task is to rotate that array by 90 degrees in an anti-clockwise direction without using any extra spac...read more
Q51. There are five glasses that are kept upside down.At a time you are bound to turn four glasses.Give minimum number of times in which you can turn back all the glasses so that now none among them are upside down
Minimum number of times to turn all glasses upside down when 4 can be turned at a time.
Turn over any four glasses, leaving one untouched.
Repeat the above step until only one glass is left upside down.
Finally, turn over the last glass to complete the task.
Minimum number of turns required is 3.
Given a string of integers ‘bin’. Return 'true' if the string represents a valid binary number, else return 'false'. A binary number is a number that has only 0 or 1 in it.
Input Format...read more
You are given a graph with 'N' vertices numbered from '1' to 'N' and 'M' edges. You have to colour this graph in two different colours, say blue and red such that no two vertices connected by an...read more
You are given an array/list 'NUM' of integers. You are supposed to rearrange the elements of the given 'NUM' so that after rearranging the given array/list there are no two adjacent elements ...read more
Given a binary tree with N number of nodes, check if that input tree is BST (Binary Search Tree) or not. If yes, return true, return false otherwise.
A binary search tree (BST) is a binary tree data...read more
Given an integer number ‘num’. Your task is to convert ‘num’ into a word.
Suppose the given number ‘num’ is ‘9823’ then you have to return a string “nine thousand eight hundred tw...read more
There are n glasses on the table, all standing upside down. In one move, you are allowed to turn over exactly n – 1 of them. Determine all values of n for which all the glasses can be turned up in the min...read more
You are given a string 'STR'. The string contains [a-z] [A-Z] [0-9] [special characters]. You have to find the reverse of the string.
For example:
If the given string is: STR = "abcde". You hav...read moreYou are given an array 'ARR' of N integers. Each integer represents the height of a balloon. So, there are N balloons lined up.
Your aim is to destroy all these balloons. Now, a balloon can onl...read more
Q60. There are 25 horses in which you need to find out the fastest 3 horses. you can conduct a race among at most 5 horses to find out relative speed. At no point, you can find out the actual speed of the horse in a...
read moreMinimum 7 races required to find the top 3 fastest horses.
Divide the 25 horses into 5 groups of 5 horses each.
Conduct a race among the horses in each group to determine the fastest horse in each group.
Take the top 2 horses from each group and conduct a race among them to determine the fastest horse overall.
The winner of this race is the fastest horse.
Now, take the second-place horse from the final race and the second-place horse from each group race.
Conduct a race among these...read more
Q61. 4. What is marker interface? Example of marker interface. Why it is used.
Marker interface is an interface with no methods. It is used to mark a class for special treatment.
Marker interface is used to provide metadata to the JVM.
It is used to indicate that a class has some special behavior or characteristics.
Example: Serializable interface in Java.
Marker interfaces are used for reflection and serialization.
They are also used in frameworks like Spring and Hibernate.
Marker interfaces are also known as tagging interfaces.
They are used to group classes...read more
Q62. There are 25 horses and only 5 horses can be raced at a time and the top 3 are announced in each such race. What is the minimum number of races required to find the top 3 among 25 horses
The minimum number of races required to find the top 3 among 25 horses is 7.
Divide the 25 horses into 5 groups of 5 horses each.
Race the 5 groups, which will give us the top 3 horses from each group.
Now we have 15 horses remaining.
Race the top 3 horses from each group, which will give us the top 3 horses overall.
This requires a total of 7 races.
Q63. Code: – Given the value of a starting position and an ending position, you have to reach from start to end in a linear way, and you can move either to position immediate right to current position or two step ri...
read morePrint all possible paths from start to end in a linear way, moving either one or two steps right.
Use dynamic programming to solve the problem
Create a 2D array to store the number of paths to each position
Start from the end position and work backwards
At each position, calculate the number of paths by summing the number of paths from the next two positions
Print all the paths by backtracking from the start position
Given a Binary Search Tree (BST) and a range [min, max], remove all keys which are outside the given range. The modified tree should also be BST.
Input format:
The first l...read moreYou are given two Singly Linked List of integers, which are merging at some node of a third linked list.
Your task is to find the data of the node at which merging starts. If there is...read more
Q66. 2. Write a program to capitalise all the first letter of a word in a sentence.
A program to capitalize the first letter of each word in a sentence.
Split the sentence into words
Loop through each word and capitalize the first letter
Join the words back into a sentence
Design and implement a data structure for Least Recently Used (LRU) cache to support the following operations:
1. get(key) - Return the value of the key if the key exists in the cache, o...read moreNinja is having a good time in solving new questions of Binary Trees from Code Studio. He is now encountered with a question having statement as "You are given a binary tree consisting of 'N' n...read more
Q69. #Introduction 1. What is White box testing, Black box testing, Grey box testing? 2. Explain Bug Life cycle? 3. What is Deferred? 4. Open Flipkart application, Search for Some product eg, phone, Write the test c...
read moreInterview questions for Test Engineer position covering topics like testing types, bug life cycle, constructors, locators, and priority/severity.
White box testing is testing the internal structure of the application, black box testing is testing the functionality without knowledge of internal structure, and grey box testing is a combination of both.
Bug life cycle includes stages like new, open, assigned, fixed, verified, and closed.
Deferred means postponing the bug fix to a l...read more
Given a sequence of numbers ‘ARR’. Your task is to return a sorted sequence of ‘ARR’ in non-descending order with help of the merge sort algorithm.
Example :
Merge Sort Algorithm - Merge sor...read moreYou have 10 coins….arrange them in 4 straight lines such that each line contains 4 coins, without picking up the pencil.
Given a binary tree with 'N' number of nodes, convert it to a Greater Tree such that data of every node of the original BST is changed to the original node’s data plus the sum of all node’s d...read more
Q73. 6. Consider an array of String, remove those string from array whose length is less than 3.
Remove strings from an array whose length is less than 3.
Loop through the array and check the length of each string.
If the length is less than 3, remove that string from the array.
Use a for loop or filter method to remove the strings.
Example: ['cat', 'dog', 'bird', 'elephant'] -> ['cat', 'dog', 'bird', 'elephant']
Example: ['a', 'to', 'the', 'in'] -> ['the', 'in']
Given a binary tree of integers, you are supposed to modify the given binary tree to a sum tree where each node value is replaced by the sum of the values of both left and r...read more
Ninja is given a task to implement a priority queue using Heap data structure. The Ninja is busying preparing for the tournament., So he asked for your help.
Your task is to use the cl...read more
Why Java is platform independent and JVM platform dependent?
Q77. 4. When to use list and when to use linked list.
Lists are used for small collections, linked lists for large or frequently modified collections.
Use lists for small collections that don't require frequent modifications.
Use linked lists for large collections or collections that require frequent modifications.
Linked lists are better for inserting or deleting elements in the middle of the collection.
Lists are better for accessing elements by index.
Example: Use a list to store a small list of names, use a linked list to impleme...read more
Write a query that joins two tables A and B having common attribute ID and selects records(ID_NAME) that have matching ID values in both tables .
Q79. How can you create a 3-tier architecture? What are the alternatives of Load Balancer? How can you create PV and PVC in Kubernetes? How much you know about the cloud and networking? How on-prem is different from...
read moreAnswering questions related to 3-tier architecture, load balancer alternatives, PV and PVC creation in Kubernetes, cloud and networking, on-prem vs cloud, and server migration tools.
To create a 3-tier architecture, separate the presentation layer, application layer, and database layer into three distinct tiers.
Alternatives to Load Balancer include DNS-based load balancing and IP-based load balancing.
To create PV and PVC in Kubernetes, use the kubectl command-line tool or YAML...read more
Q80. Modified Balanced Parentheses where a character can be matched with any other character, i.e. / with &, ! with ? and so on.
Modified Balanced Parentheses where characters can be matched with any other character.
Use a stack to keep track of opening characters
When encountering a closing character, check if it matches the top of the stack
If it matches, pop from the stack, else return false
Continue until end of string, return true if stack is empty
Q81. Spring Collections Difference between list and set What is sorted mean in hashed set java Serialization Exceptions How can you give an exception to caller method Unix- how to move a folder without giving yes/no...
read moreInterview questions for Software Developer related to Spring, Collections, Serialization, Exceptions, Unix, Annotations, Json, Build tools, Restful services, and more.
List and Set are both collection interfaces in Java. List allows duplicates and maintains insertion order while Set doesn't allow duplicates and doesn't maintain any order.
Sorted in Hashed Set means that the elements are stored in a sorted order based on their hash code.
Serialization is the process of converting...read more
Q82. What are abstract classes in Java and what is the difference between an abstract class and an interface
Abstract classes in Java are classes that cannot be instantiated and are used as blueprints for other classes.
Abstract classes cannot be instantiated, meaning you cannot create objects of an abstract class.
Abstract classes can have both abstract and non-abstract methods.
Interfaces in Java are similar to abstract classes, but they cannot have any method implementations.
A class can implement multiple interfaces, but it can only extend one abstract class.
Abstract classes can hav...read more
What is the difference between Clustered and Non-clustered index?
Q84. What is the difference between a micro controller and a micro processor?
Microcontroller is a self-contained system with memory, peripherals and processor, while microprocessor only has a processor.
Microcontroller has on-chip memory and peripherals, while microprocessor requires external memory and peripherals.
Microcontroller is used in embedded systems, while microprocessor is used in general-purpose computing.
Examples of microcontrollers include Arduino, PIC, and AVR, while examples of microprocessors include Intel Pentium, AMD Ryzen, and ARM Co...read more
Q85. Given an array of strings, print all the possible combinations of strings created by picking one character from each string of the array. The individual strings do not contain any duplicates. Ex: {ABC, DE} Ans ...
read morePrint all possible combinations of strings by picking one character from each string in the array.
Iterate through each character of the first string and combine it with each character of the second string.
Repeat the process for all strings in the array to get all possible combinations.
Use nested loops to generate combinations efficiently.
Q86. Write a code for inserting two numbers in a text file given n2>n1 and the next entry should not be overlapping like if first was 4,6 next can't be 5,7.the second n1 has to be greater than first n2
The code inserts two numbers in a text file, ensuring that the second number is greater than the first and there is no overlap between entries.
Read the existing entries from the text file
Check if the new numbers satisfy the conditions
If conditions are met, insert the new numbers into the file
Otherwise, display an error message
Let's say I give you a number 1,53,345 (I don't remember exactly). Write a program that will take the above number as input array and give output as "One Lakh Fifty-Three Thousand Three Hundre...read more
What do you mean by virtual functions in C++?
What is the major difference b/w 32-bit and 64-bit processors?
Q90. 10. Write a program to separate even and odd numbers using Java 8.
Program to separate even and odd numbers using Java 8.
Use Java 8 Stream API to filter even and odd numbers
Create two separate lists for even and odd numbers
Use lambda expressions to filter the numbers
Example: List
evenNumbers = numbers.stream().filter(n -> n % 2 == 0).collect(Collectors.toList()); Example: List
oddNumbers = numbers.stream().filter(n -> n % 2 != 0).collect(Collectors.toList());
You have 10 coins one of them is defective. You have a weight scale. How will you identify the defective coin?
What are the differences b/w Mutex and Semaphore?
What is the difference b/w Abstract Class and Interface in Java?
Q94. 3. How to remove sensitive information from serializable interface.
Sensitive information can be removed from serializable interface by implementing custom serialization.
Create a custom serialization method that excludes sensitive information.
Use the transient keyword to mark sensitive fields as non-serializable.
Consider using encryption or hashing to protect sensitive data.
Test serialization and deserialization to ensure sensitive information is not included.
Examples: exclude passwords, credit card numbers, and personal identification inform...read more
Q95. Can an array have elements of different data types?
Yes, an array can have elements of different data types.
An array can have elements of different data types, but it's not recommended.
It can make the code harder to read and maintain.
For example, an array can have both strings and numbers: ['apple', 5, 'banana']
What is the main difference between UNION and UNION ALL?
Q97. Subset sum variant, find missing number using single loop, difference between two dates, , Core Java concept , Sql, finding duplicate number in list, finding loop in linkedlist, finding node where cycle starts ...
read moreInterview questions for Application Engineer role covering various topics.
Subset sum variant - finding a subset of numbers that add up to a given sum
Single loop missing number - finding a missing number in an array using a single loop
Difference between two dates - calculating the difference between two dates in Java
Core Java concepts - knowledge of basic Java concepts such as inheritance, polymorphism, etc.
SQL - knowledge of SQL queries and database management
Finding duplicat...read more
How to find the pre order traversal of a tree?
State complexity of merge sort
Questions based on radix sort
What will be the result when we will add two binary numbers in 64Bit and 32 Bit operating system?
Q100. Describe in steps how you downloaded any software recently
I recently downloaded VLC media player.
Visited the official website of VLC media player
Clicked on the download button
Selected the appropriate version for my operating system
Waited for the download to complete
Opened the downloaded file and followed the installation wizard
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