HTML
Disclosure: This article may contain affiliate links. When you purchase, we may earn a commission.

8 Examples of Primitive Data Types In Java (int, long, boolean, float, double, byte, char, and short)

Hello guys, Data types are first few things you should learn when you start learning a programming language and when it comes to learn Java, there are 8 primitive data types which you should know. These are divided into three categories, numeric, text, and boolean values. Numeric data types can be further divided into two like natural numbers and floating pointing numbers. But, Before we get to a list of the 10 examples of primitive data types in Java, let me tell you a little bit more about what the primitive data types are.  There are essentially 8 primitive data types in Java. They are int, byte, short, long, float, double, boolean, and char. The primitive data types are not considered objects and represent raw values. These primitive data types are also stored directly on the stack.

15 Linked List Interview Questions for Software Engineering Interviews

Hello guys, if you are preparing for Software Development interview or want to become a Software Engineer in 2023 then you must pay full attention to two important topics: first is Data Structure and Algorithms, and second is System Design. These two topics are very essential and you will always find questions from these in any coding interview. They are also the most difficult to crack as they are very vast, no matter how much you will prepare there will be certain questions which you don't know but if you have solid knowledge of fundamental data structure like array, linked list, binary tree, hash table, heap, and graphs as well sorting and searching algorithms like quicksort, merge sort, selection sort, insertion sort, binary tree as well advanced String and graph algorithms then you can still do well.

What is temporary table in Database and SQL? Example Tutorial

Hello folks, if you have heard the term temporary table online or by your colleague in a call and wondering what is temporary table, what is the difference between a normal table and a temporary table, and when and how to use it then you have come to the right place. In this blog, we shall learn how to use a temporary table in SQL. But before we go into that we need an overview of SQL. What is SQL? SQL stands for Structured query language. it is a programming language used in communicating or relating to the relational database. And this programming language performs various forms of operation in the data. It was created in the 1970s, SQL is used by database administrators, and developers writing data integration scripts, etc.

Top 20 PL/SQL Interview Questions with Answers in 2023

Hello guys, if you are preparing for Oracle or PL/SQL Job or a Developer job where PL/SQL skills are needed and looking for frequently asked PL/SQL Interview Questions then you have come to the right place. Earlier, I have shared both best PL/SQL courses and best PL/SQL books and in this article, I am going to share popular PL/SQL Interview Questions you can revise before your interview. Preparing for PL/SQL Interview is not a rocket science and you can prepare for it the same way you prepare for other interviews. 

Top 20 Web Development Interview Questions with Answers in 2023

Hello guys, if you are preparing for web developer job and looking for popular web development interview questions for preparation then you have come to the right place. Earlier, I have shared HTML Interview Question, CSS Interview Questions, and JavaScript Interview Questions and in this article, I am going to share common web development interview questions. You may be thinking how much different it is from other list but this is a general questions about web development like web services, images, SOAP, REST, Pagination etc.

How to use EXISTS and NOT EXISTS in SQL? Microsoft SQL Server Example

Hello guys, if you are wondering how to use the IF EXISTS and NOT EXISTS in SQL then you are at the right place. Earlier, I have shared how to use GROUP BY, WHERE, and HAVING clause and in this tutorial I will share how to use exists and not exists clause in SQL. The IF EXISTS and NOT EXISTS commands in T-SQL are covered in depth in this article. When comparing data sets using subqueries, it also illustrates why EXISTS should be preferred over IN and NOT EXISTS over NOT IN. If you don't know, EXISTS is a logical operator in SQL that is used to check if rows in a database exist. If the subquery produces one or more records, it returns TRUE. The NOT EXISTS operator in SQL is the polar opposite of the EXISTS operator, and it is fulfilled if the subquery returns no results.

Spring HelloWorld Example in Java Annotations and Autowiring [Tutorial]

Spring framework has gone a couple of releases since I last share the Spring hello world example with XML configuration. In this article, I am going to explain to you how to create a Spring hello world example with Spring 4.2 release and by using Annotation for dependency injection and autowiring. So no more XML files to specify bean dependencies. It's a simple program that shows how you can use the Spring framework to create Services that are loosely coupled. The example will show you the basic concept of dependency injection by creating a simple Java application that greets the user.

Top 20 DevOps Interview Questions with Answers for Experienced Developers in 2023

Hello guys, if you are preparing for DevOps Engineer job interview or a Developer interview then preparing DevOps questions is quite important. I have seen a couple of DevOps related questions on Java developer interview in last a couple of years. Interviewers are now expecting you to become familiar with Cloud, DevOps and essential DevOps tools like Docker, Kubernetes, Ansible, Terraform tec. If you have been moving around looking for a way which will help you pass your DevOps interview that is around the corner, you have come to the right place at the right time. 

Top 18 CSS Interview Questions and Answers for 1 to 2 years experienced

Hello guys, if you are preparing for web developer interview then you must prepare for CSS Interview questions. CSS is one of the three core technologies of the World Wide Web(WWW). A website is incomplete without CSS. The first feature of a website noted by the visitors is its presentation. It does not matter how excellent the behind-the-scenes of a website are, if the client-side view is not appealing, the website is almost a failure. Thus, CSS is as important as JavaScript

10 Examples Of Printstream print(), println() and prinf() In Java

Hello guys, if you are working in Java or just started with Java then you have must come across statements like System.out.println("Hello world") to print something on console or command prompt. This is actually the first statement I wrote in Java when I started programming and at that time I didn't realize how it work and what is System and PrintStream class and what is out here but now I know and I am going to explain all this to you in this article, along with PrintStream class and its various print methods like print(), println() and particularly printf() to print various objects in Java. But,   Before we get to the 10 examples of Printstream printf() in Java, let me tell you a little bit more about what exactly Printstream is. 

Top 50 Database and SQL Interview Questions Answers 1 to 5 Years Experienced

Hello guys, whether you are preparing for Java developer interview or any other Software Developer Interview, a DevOps Interview or a IT support interview, you should prepare for SQL and Database related questions. Along with Data Structure, Algorithms, System Design, and Computer Fundamentals, SQL and Database are two of the essential topic for programming or technical Job interview. In the past, I have shared many questions related to MSSQL questions, Oracle Questions, MySQL questions, and PostgreSQL questions and in this article, I am going to share both theory based and query based Database and SQL Interview questions with to the points answers.

How to solve KnapSack problem in Java using dynamic programming? Example Tutorial

 Problem Statement: 

You are given a KnapSack of a maximum capacity of 'W' and N items each with its own value and weight associated with it, You have to find the max value item(s) that we can put in the KnapSack of the capacity 'W'.

                                                   

                                       

                                                                  KNAPSACK PROBLEM 


Let's collect more input & apply the thought process?

The total weight we can put in the bag is either 8 kg or less.

But keep in mind that you can't fill an item more than one time. Repetitions are not allowed.

We are given 2 arrays, weight & value, as input data.

Finally, we need to generate/print the max value.

How to determine whether the problem can be solved using the DP(Dynamic Programming) or not?



Let's try to solve it...


If you have noticed it is talking about the max value so we can say that it is a kind of optimization problem and we know that we can solve such a problem by using dynamic programming but it is tricky.

Consider the below matrix of knapsacks of different capacities where rows present the items to be put in the knapsack and the columns represent the knapsacks with different capacities(weights). Each cell represents the value of the given item to be put in the bag.

                                                  --------- KnapSacks with different capacities---->

                                        

We have to find the value of the last bottom right cell to get the max value for an 8 kg knapsack.



Go In Depth...

Ask yourself why we came up with such a matrix?

In order to calculate the max value for the 8 kg KnapSack, we will have to calculate the max values of the smaller capacities KnapSacks represented as 7, 6, 5, 4, and so on.


Now let's see how it works.

For the marked cell 'matrix[2][8]' we will generate the max value using dynamic programming property.

The diagram says that the values that can be put in this cell are 1, 3, and 4.

After applying the dynamic prog. property and remove the 4 kg weight item from the marked cell.

So my problem reduces to 4 kg KnapSack with items 1 and 3. Let's say we already calculated the max value 'x' for this KnapSack.



We can use this value 'x' to calculate the value of the marked cell. And the value will be x+50.

So what we did?

We just added the 4 kg weight item's value(50), which we removed from the bag in the previous step, back to the 8 kg KnapSack in the marked cell.

So the value of the marked cell, x+ 50, represents the value in 8 kg KnapSack using items 1, 3, and 4.

Now the question is it is mandatory to use items 1, 3, and 4 to put the max value in 8 kg KnapSack?

No, because the max value can be generated with values 1, and 3 as well, and consider that value is 'y'.

So finally the maximum value for the marked cell will be:

   matrix[2][8] = max(x+50, y);

for the given 8 kg KnapSack.

**So this is the core logic we will use to solve this problem.

Let's take another example

Suppose we are given a KnapSack of 7 kg with items 1, 3, 4, and 5 to find the value of the cell highlighted.



Apply the same logic as the above example i.e. remove the 5 kg item.

So after removing the weight the new KnapSack comes out with a weight of 2 kg with items left are 1, 3, and 4.

Again emphasize what logic we are using ????

🤔🤔🤔

So basically whatever row we select to generate the max value of the cell, we selected the last row of the 5 kg weight item, and we remove the weight of that item from the given KnapSack as well as from the list of items.

              Given KnapSack                  New KnapSack

                          7 ---------removing 5 ---------> 2

                  {1, 3, 4, 5}----removing 5 -----> {1, 3, 4}


Now let's assume that the new KnapSack generates max value 'z'. Again apply the same logic as applied in the previous example to generate the max value for the highlighted cell for 7 kg KnapSack.


The value of the removed 5 kg weight item is 70 so again adding it back to the KnapSack the value of the highlighted cell becomes 'z+70'.


Now consider that the value of the cell just above the highlighted one is 'y' then we can say that the value for the desired cell will be:


        matrix[3][7] = max(z+70, y);


Note: Please note that the 'y' is also generated using the same logic i.e. the max of the cells above it.

       y = max(matrix[0][7], matrix[1][7]);


So keep in mind that this is the basic logic to solve this problem.


Now start filling this matrix...



For the knapsacks 1, 2, ...., 8 the max value with a given item of weight 1 kg will be 10.


Now come to the 2nd row. The max values for knapsacks 1, and 2 with given items 1 and 3 will be 10 only because the knapsack total weights 1 and 2 are less than 3 kg weight item.


Pick the value of any cell and apply the logic you will understand how the max value got generated.

But let me again explain to you for the cells 'matrix[1][3]' and 'matrix[1][4]'.


    Given KnapSack                          Generated KnapSack

            

               3 ----------removing 3 ---------- 0

    Items Given                                 Items Left

       { 1, 3 } ---------removing 3 ------{ 1 }




The weight of the generated knapsack '0' is 0 kg so we can't put the value(10) of the item{1} left. So the max value for the new knapsack will be 0.


Now as per our logic again add removed the 3 kg weight item back to the knapsack so finally, the max value for the given knapsack 3 will be generated '0 + 40'.

Now the value above the cell 'matrix[1][3]' is 10.


So matrix[1][3]  = max(0 + 40, 10) = 40. 


Similarly, the max value for the 8 kg knapsack will be 110.


Implementation:


Now let's covert the above problem into code.

The below logic shows how to fill the matrix above.


for(int i = 0; i < weight.length; i++){


        for(int j = 0; j <= W; j++){


           matrix[i][j] = Max(matrix[i-1][j-weight[i]] + value[i] , matrix[i-1][j]);


        }

}


weight: Given an array of items weights.


value: Given an array of the item values.


The outer for loop prints the rows and the inner one prints the columns of the matrix.


The equation


  matrix[i][j] = Max(matrix[i-1][j-weight[i]] + value[i] , matrix[i-1][j]);  


is playing the main role. 


This represents the core logic that I explained to you to calculate the cell value.


Complete Code: 


    public class Main

    {

        public static int knapSackProblem(int[] value, int[] weight, int W)

        {

            

            

            int[][] matrix = new int[value.length + 1][W + 1];

   

            

            for (int i = 1; i <= value.length; i++)

            {

                

                for (int j = 0; j <= W; j++)

                {

                    

                    if (weight[i-1] > j) {

                        matrix[i][j] = matrix[i-1][j];

                    }

                    else {

                        

                        

                matrix[i][j] = Integer.max(matrix[i-1][j],matrix[i-1][j-weight[i-1]] + value[i-1]);

                    }

                }

            }

   

            

            return matrix[value.length][W];

        }

   

        public static void main(String[] args)

        {

            

            int[] value = { 10,40, 50, 70 };

            int[] weight = {  1,3,4,5 };

   

            

            int W = 8;

   

            System.out.println("Value is "+ knapSackProblem(value, weight, W));

        }

    }


Test Your Understanding...


Q. 1) Given KnapSack W = 9 kg and items with different weights and corresponding values are:


                

Weight

value

1

80

4

70

5

90



What could be the max value after putting the items in the bag so that the total weight <= 9 kg?


Ans. 160


Before you Leave...

Knowledge of data structure and algorithms is must to simulate the real world problem in code.

If you want to learn more about this article, drop a comment below and reach out to us to let us know your interest.

If you enjoyed learning the fundamentals of DSA share your knowledge to your fellow programmers and social circle. May be someone out really needs this resource, and you might be helping them out by sharing it.

Top 21 Git Interview Questions and Answers for Programmers and DevOps in 2023

Hello guys, if you are preparing for Software developer interview then you should prepare for Git, one of the essential and most popular version control and source control tool in Software industry. Almost every company, both big and small are now using Git to store their source code and conduct code reviews, yes the code review is one of the main reason many organization shifted to Git. Both Github and BitBucket provides in-built code review features which also promote good software development practices. 

Top 5 Free Amazon Web Services or AWS Courses to Learn in 2023- Best of Lot [UPDATED]

Hello guys, if you are thinking about learning cloud technologies or cloud computing, and looking at the various cloud providers like AWS, GCP, or Azure, then you are going in the right direction. The future lies with Cloud, and it's essential for every developer to learn about cloud computing solutions. When we talk about Cloud, the first thing that comes to mind is AWS, the biggest Cloud Computing platform, and that's why I suggest a lot of developers learn it. If you want to learn Amazon Web Services, popularly known as AWS, and looking for some excellent resources like books, courses, and tutorials, then you have come to the right place.

Top 5 Free Courses to Learn Microservices for Java Developers in 2023 - Best of Lot

Hello Java programmers, if you want to learn Microservice architecture and look for free Microservice resources like free online courses, you have come to the right place. Earlier, I have shared the best Microservice courses for Java programmers to build Microservice using Java and the Spring framework, and today, I will share some free courses to learn Microservice in Java using Spring Boot and the Spring Cloud framework. If you don't know, Microservices is a modern architecture that goes along nicely with cloud computing and makes deployment, scaling, and even development easier. 

Top 6 Free Python Courses for Beginners to Learn Programming in 2023 - Best of Lot

Hello guys, If you are a beginner looking for best Free Python resources to start your programming journey, like books and online courses then you have come to the right place. Earlier, I have shared a couple of free Python Programming books and some of the best courses to learn Python, which were not free. Some of my readers asked me to share some free online courses to learn Python, and it made sense. I personally like starting from free resources, and today, I'll share a couple of excellent Python programming courses, which are absolutely FREE. You can take these online courses to learn Python at your own pace, at your own time, and at your place to learn Python in 2023. This is an excellent advantage of online learning, the flexibility it provides is just impressive. 

Top 10 Free Udemy Courses To Learn Coding in 2023 - Best of Lot

When I was a little kid, I remember reading somewhere that coding will be the language of the future. I was intrigued. What was this new language that I didn't know about and nobody around me spoke? How was it going to be the language of the future?

Before we get to the 10 free Udemy courses that will teach you coding, let me tell you a little more about what coding is.