Hey everyone, I hope you are all doing great. Welcome to Simply Learn's YouTube channel and today we will be discussing about the coding interview questions. We will begin this video with some conceptual questions about data structures, algorithms and then move on to discussing the coding problems that are most commonly asked to solve in the interviews.
These questions will help you summarize every important programming concept and serve as perfect preparation resource for coding interviews. By the end of this video, I can assure you that you will have a proper understanding of data structure concepts and you will be able to code the most common problems asked in interviews. So, let's get started with an exciting video on coding interview questions.
Before we begin, please make sure to subscribe to our YouTube channel and hit that bell icon to never miss an update from Simply Learn. So I hope I was clear with the agenda. Now let's begin with the Top 40. coding interview questions that you should know. Programming interview questions are an integral part of an interview for the developer's position. No matter which programming language you master, it is expected that you are familiar with the fundamental concepts of the programming.
Coding skills are always the deciding factor in any programming interview. We will discuss the top 40 coding interview questions you should absolutely know how to crack in interviews to get your dream job. So without further ado, let's get started.
So, as discussed, the first part would be the conceptual interview questions. In that, the first question we have to face is, what is a data structure? So the answer for this question is, a data structure is a storage format that defines the way the data is stored, organized and manipulated. Some popular data structures are, arrays, trees and graphs. Moving ahead, we have our next question that is, what is an array?
So basically, All the items that an array stores are of the same data type. It organizes data so that a related set of values can be easily sorted or searched. Now followed by an array, the next question we have is about the linked list.
So what is a linked list? It is completely similar to array but there are some basic differences. Like an array, a linked list is a linear data structure in which elements are not necessarily stored in a continuous manner.
So, linked list is basically a sequence of nodes where each node points to the next node forming a chain like structure. So, followed by the linked list, we have the next question which is based on stacks. So, what exactly is a stack?
Stack is a linear data structure that performs operations in a LIFO order. So, in a stack, elements can only be accessed starting from the topmost to the bottom element. So, followed by stacks, we have our next question which is, what is a LIFO? So, basically LIFO stands for Last In First Out.
So, it is a way of accessing, storing and retrieving data. The data that was stored at the last is extracted at the first. The next one after LIFO is a Queue. So, what exactly is a Queue? Queue is a linear data structure that performs operations in a FIFO order.
So, basically FIFO is First In First Out. In a Queue, the least recently added elements are removed first as opposite to the stack. So, up next we have the FIFO.
So, what exactly is FIFO? FIFO stands for first in first out. It is a way of accessing, storing and retrieving data.
The data that was stored first is extracted first. The next question is about the binary trees. So, what exactly are binary trees?
A binary tree is an extension of linked list data structure where each node has two children. Binary tree has two nodes at all the times, a left node and a right node. So, these left and right nodes for the top node are known as children of the top node.
Next we have is recursion. So, what is recursion? Recursion refers to a function calling itself based on a terminating condition. It uses last and first start functionality and therefore makes use of the stack data structure. Followed by recursion, we have the OOPS.
So, what is the OOPS concept? OOPS stands for Object Oriented Programming System. A paradigm that provides concepts such as Objects, Classes, Inheritance, Polymorphism, Encapsulation, etc. So, what are the concepts introduced in OOPS?
So, the following concepts are introduced in OOPS. They are Object, Class, Inheritance, Polymorphism, Abstraction and Encapsulation. Now, we will discuss each one of them in a bit more detail. So, we will begin with Object. A real world entity having a particular state and a behavior is called as an Object.
It can be defined as an incident of a class. So, next we have the class, a logical entity that defines the blueprint from which an object can be created or instantiated is called as a class. So, basically class is a blueprint which we use to create an object.
So, followed by classes and objects, we have the inheritance, a concept that refers to an object acquiring all the properties and behaviors of a parent object is called as inheritance. So, basically inheritance provides code reusability. So, followed by inheritance, the next important concept we have is the polymorphism.
So, polymorphism is a concept that allows the task to be performed in different ways. In Java, we use method overloading and method overriding to achieve polymorphism. Followed by polymorphism, we have the abstraction.
A concept that hides the internal details of an application and shows only the functionality is called as abstraction. In Java, We use abstract classes and interface to achieve abstraction. The last one is the encapsulation.
Encapsulation is a concept that refers to wrapping of code and data together into a single unit. So basically, every code we have in the Java will have data members and data manipulating methods. So, encapsulation is a basic concept that brings them together and binds them as a single unit.
So, followed by oops concepts, the next important question that we will be facing is about, the binary search tree. So explain binary search tree. A binary search tree stores data in such a way that it can be retrieved very efficiently. Next, the left subtree contains nodes whose keys are less than that of the node's key value. The right subtree contains nodes whose keys are greater than or equal to the node's key value.
Followed by that the next question we have is the doubly linked list. So what exactly are doubly linked lists? The doubly linked list are special type of linked list in which traversal across the data elements can be done in both directions.
This is made possible by having two links in which one of the node will be connected to the next upcoming node and the other link is connected to the previous node. So, followed by the doubly linked list, the next important question we have is the graph. So, what exactly is a graph?
A graph is one type of data structure that contains a set of ordered pairs. So, these ordered pairs are also referred as edges or arcs and arcs are used to connect nodes where data can be stored or retrieved. So, followed by this, we have our next question that is called as the difference between linear and non-linear data structures.
So, the first difference is the linear data structure in which data elements are adjacent to each other and the non-linear data structure is a structure in which each element can connect to two adjacent data elements. Followed by that, the next difference is Examples of linear data structure are the arrays, linkless stacks and others like Qs and examples for non-linear data structures are trees and graphs. Followed by that the next question is what is a DQ? So DQ is a double-ended Q and this is a structure in which elements can be inserted or removed from either end.
Followed by that we have our next question which says the difference between the stack and an array. So, stack follows a LIFO pattern. It means that the data access follows a sequence in which the last data to be stored is the first element to be extracted.
Next, we have the array. Arrays, on the other hand, do not follow a particular order and instead can be accessed by referring the indexed element within the array. Followed by that, the next question is, which sorting algorithm is the best? There are many types of sorting algorithms like quick sort, bubble sort, balloon sort, radix sort, merge sort, etc.
And no algorithm can be considered as the best or the fastest, because each is designed for a specific type of data structure, where it performs the best. And our 19th question is, how does variable declaration affect memory? So the amount of memory can be allocated or reserved depends on the data type being stored in that variable. For example, if a variable is declared to be integer type, then 32 bits of memory storage will be reserved for that variable. So, the 20th question is, what are dynamic data structures?
So, dynamic data structures are the data structures that expand and contract as the program runs. It provides a flexible means of manipulating data because it can adjust according to the size of the data. So, these were the conceptual based questions so far we discussed now.
Next we will move ahead into the programming interview questions. So, at first we have, how do you reverse a string in Java? So, you can see on my screen, we have a code segment that is capable of reversing a string. So, basically you declare a string, then take the length of that string, loop through the characters of the string and add these characters in the reverse order, then print the resultant string.
Next, we have, how do you determine if a string is a palindrome or not? So, for that particular question, we have a code segment which is capable to reverse the string and check if it is a palindrome or not and accordingly provide the result. So, a string is a palindrome when it stays the same on the reversing order of characters in that string.
It is achieved by reversing the original string first and then checking if the reverse string is equal to the original string or not. Followed by that, we have the 23rd question that says, find the number of occurrences of a string character in a string. So, the following code segment is capable to find that particular task and to find the number of occurrences of loop through the string and search for that character in every iteration whenever it is found, then the count will be updated.
Followed by that, the 24th question is, find if the given two strings are anagrams or not. Two strings are considered as anagrams if they contain similar group of characters in varied sequence. For finding out if two strings are anagrams or not, we have the code segment on the right part of my screen right now.
So basically you declare a boolean value that tells the end of the two strings are anagrams or not. Then first check the length of the both strings if they are same or not. Then if they are not same, then they are not anagrams.
If they are same, then they are anagrams. Like they might be a chance of being the two strings as anagrams. And followed by the next step is convert both the strings to character arrays then sort them out. And finally, check the sorted arrays if they are equal or not.
If they are equal, then print their anagrams. And if they are not equal, then you should print not anagrams. The next 25th question is, how do you calculate the number of vowels and consonants in a string?
So, you can see on my screen, I have a code segment, which will be capable of counting vowels and consonants in a string. So, loop through the string. So, that's the first step. Followed by that, increase the vowel variable by 1 whenever the character can be found as a vowel using the...
if condition, otherwise increment the consonant variable. Finally, print the values of both the vowels and consonants count. The next important question we will be facing in the coding interview is how do you get matching elements in an integer array?
So for that, we have a code segment on my screen right away. Now the steps for that are declare an array, nest a couple of loops and compare the numbers with the other numbers in the array and finally print the matching elements whenever found. So, next we have this 27th question that says, code bubble sort algorithm. You don't have to code the entire bubble sort algorithm.
What you can do is just write the code segment, which has a logic for it. So, that is currently on my screen right now. So, what you basically do is declare an array.
So, next what you do is nest a couple of loops and compare the numbers in that array. And then the array will be sorted in the ascending order by replacing the elements if found in any other order. 28th question is, Code the insertion sort algorithm.
So, this is completely similar approach. What we followed for the bubble sort, you just have to write the code segment of logic. So, the steps will be, first the element in the array is assumed to be sorted. Take the second element and then store it separately in key.
Now, the first two elements are like sorted. Take the third element and then compare it with the elements in the left of it. The process goes on until the array is sorted.
So, next we have the 29th question, how do you reverse an array? So, you can see on my screen, we have a code segment that says how to reverse an array. Loop till the half length of the array.
Next, we have to replace the numbers corresponding to the indexes from the starting to the end. Followed by that, we have the 30th question where we have to find a way to swap two numbers without the third variable. So, this type of interview question will be asked most number of times to the beginners, most frequently.
Now, the solution for that has been written on my screen right away. You can check out that. And the steps to be followed are declare two variables and initialize them with the values.
Make b the sum of both the numbers. Then, subtract the sum, that is the b, from a. So, a is now swapped. Lastly, subtract a from the sum b.
So, b is now also swapped. Next, we have the 31st question which says, print a Fibonacci series using recursion. So, for that we have a code segment which can print a Fibonacci series on my screen right now. So, the code on my screen can be used to print the Fibonacci series.
So, basically what are Fibonacci numbers? So, the Fibonacci numbers are the numbers in the following integer sequence 0, 1, 1, 2, 3, 5, 8, 13, 21 and so on. They can be calculated using the mathematical formula used in the Fibonacci recursive function.
The next question you will be facing is how do you find the factorial of an integer? we have the code segment on my screen which can perform the factorial of an integer operation. So, the factorial is a function that multiplies a number by every number below it.
For example, factorial of 5 is 5 into 4 into 3 into 2 into 1 which is equals to 120. So, recursive function multiplies the number until it reaches 1. The next one is how do you reverse a linked list? So for that we have the code segment on my screen right away. You can please check it out and try it. So if you can find out if it can reverse a linked list or not. So the steps to be done for that are declare a linked list first, then add elements to that linked list, apply the descending iterator method to the linked list, and then they should reverse the order of the elements in the linked list.
The 34th question is how do you implement binary search? So, for that we have the code segment right on my screen. You can check that out and the steps to be followed are mentioned in the code segment. So, the binary search divides the array into half in every iteration step until it finds the element.
It works on sorted array since it compares the values of adjacent elements and then calculates the middle number. If the value of low becomes greater than high at any point, it means the element is not present in the list. So, this is how the binary search basically works.
Followed by that, we have the 35th question which says, find the second largest number in the array. So, you can see we have a code segment on my screen to find it out. So, the steps to be followed are, loop through the array.
If the value of i is greater than the highest, store the value of i in the highest. And, store the value of highest in the second highest variable. So, now let's move ahead to the 36th question.
How do you remove all occurrences of a given character from the input string? So we have a simple small code segment on my screen right away. So that code segment can be used to remove all the occurrences of a given character from an input string.
So what you can do is use the built-in string method that is replace to replace a character with any other character including symbols and white spaces. So followed by that we have our 37th question. So that is showcase.
inheritance with the help of a program. So, we have a small code segment on my screen to showcase the one of the major object-oriented programming method that is inheritance. So, the class cat inherits the property color from class animal by extending the parent class animal.
This way, a class cat can have more parent classes if it wishes to inherit their properties as well. So, next question that is the 38th question is, Explain overloading and overriding with the help of a program. So this is a major question which is asked many number of times, most frequently for the beginners.
And sometimes even the experienced candidates cannot escape this question. So first we'll discuss overloading. When a class has two or more methods with the same name, they are called as overloaded methods. So you can see a code segment on the right side part of my screen right away. So this is an example for overloading.
Next, we will discuss the overriding. So, next we will discuss the overriding. So, when a superclass method is also implemented in the child class, then it's a clear case of overriding. So, on the right side part of my screen, you can see a code segment where a child class is extending the base class method, which is print name. Now, followed by that, we have the 39th question, that is check if the given number is prime or not.
So, you can see a code segment on my screen which determines if the given number is a prime number or not. So, the steps to be followed to find if a given number is prime or not are, use if statements to check for each condition separately. If the number is 0 or 1, it cannot be prime.
If the number is 2, it is prime. If the number is and finally the third condition you need to take care of is, if the number is indivisible by other numbers. then it is prime.
So basically prime numbers are divisible by 1 or itself. If any other number is capable to divide the number, then it is not a prime number. Now the last question in the list is how do you sum all the elements in an array? So for that we have a code segment right on my screen.
Please check it and try to run it and that's the best way to learn. So the steps to be followed are use the loop to iterate through the array and keep adding the elements in that array. And finally, you'll get the sum of the elements in the array and you can just print this sum at the last. So, with that, as you prepare for your upcoming job interview, we hope these coding questions have provided more insight into what types of questions you are likely to be asked.
And with that, we have come to an end of this video on coding interview questions. I hope it was informative and interesting. If you have any questions about any topics covered in this video, please feel free to ask in the comment section below.
Our team of experts will be happy to solve all your queries. Thank you for watching, stay safe, and keep learning.