DEV Community: Raksha Kannusami

Why I want to write

Raksha Kannusami — Wed, 27 Mar 2024 04:18:38 +0000

I always thought writing would be a piece of cake for me until it took me a good half an hour to draft the first line of this post.

If I had to draw a pie chart of what is going on in my mind at any given time, it would look like the following image -

Since I am spending so much time reading, learning and exploring, I want to get out of my comfort zone to start writing more freqeuntly, and it would be perfect to start with things that I am familiar with - Technology, cats and coffee!

I am a software engineer who loves coffee. I am a proud mom to a cat named Fia and I love her to the core even after she once broke my new laptop by biting the screen. I promise you’ll get to see a cute picture of Fia with every post of mine as a bonus.

I also love reading books that gets me hooked with inspiring stories of successful women. I will also be using this platform to share some interesting insights I have gained from these stories.

Subscribe and let’s be friends!

Here’s me keeping my promise …

Subscribe to my newsletter here - https://rakshakannusami.substack.com/

bye for now,

Raksha & Fia

What is your favorite coffee?

Raksha Kannusami — Tue, 06 Oct 2020 18:14:02 +0000

Mine is freshly double brewed black coffee.
Comment and share your favorite coffee.
because there is no code without coffee :D

Subarray | Subsequence | Subset? - The difference.

Raksha Kannusami — Tue, 22 Sep 2020 11:17:39 +0000

Have you come across these questions while practising to code?

❓ Given an array of integers that might contain duplicates, return all possible subsets.
Try the Question here ⬅️

❓ Given two sequences, find the length of the longest subsequence present in both of them. Both the strings are of uppercase.
Try the Question here ⬅️

❓ Find out the maximum sub-array of non-negative numbers from an array.
Try the Question here ⬅️

If you want to attempt these questions, you should know the difference between Subset, Subsequence, and Subarray.

Let us understand these 3 terms using a simple example.

Suppose we are given an array of numbers, {10,20,30,40,50}, we need to find: Subset, subsequence, and subarray.

Subarray:

A subarray is a contiguous sequence in an array.

{10,20,30} ✅
{10,20} ✅
{10,30} ❌

Subsequence:

A subsequence is a set of elements not necessarily contiguous but should maintain order.

{10,20,30} ✅
{10,30} ✅
{10,40,30} ❌

Subset:

A subset is a subsequence, except it also includes an empty set {}.

{10,20,30} ✅
{10,40} ✅
{} ✅

FACT: All subsets are subsequences, and all subsequences are subsets!

Now you'll never confuse these terms!

Keep learning! Keep growing! 💖

Thank you DEV! 💖

Raksha Kannusami — Tue, 15 Sep 2020 13:55:11 +0000

I'm grateful for this community.
I'm grateful to you people who encourage me.
I'm grateful for all my friends who correct me.

I'm grateful for you who is reading this. ❤️

I wrote my first article on DEV on May 28, 2020, and in a span of 130 days I published 17 posts with 17K+ views, 1000 followers, and a whole lot of learning! 🎉

Writing on this platform gave me an immense amount of learning, which I couldn't have got without DEV. Every topic I wrote about, helped me understand it deeply enough that would never forget about it.

I consider this just the beginning for me to get better at writing, learning more, and moreover helping people with the knowledge that I am gaining, one post at a time. 😊

I wish to learn more,
share more,
write more,
grow more.

Thank you again.

Do check out one of my posts which was most liked by you guys!😁

Productivity: Are you a fox 🦊 or a hedgehog 🦔?

Raksha Kannusami ・ Aug 11 '20

#productivity

keep learning, keep coding, keep growing! 💖

⭐ this GitHub repository for Array pseudo-codes! 🎉

Raksha Kannusami — Tue, 08 Sep 2020 12:28:45 +0000

I have been learning data structures and algorithms for a while and have been learning using various resources online.

I started with the simplest data-structure, Arrays.

As a part of this, I maintained a Github repository to save all the pseudo-codes so that it becomes easy for future reference.

rakshakannu / Datastructures-arrays

collection of various problems and solutions on array data structure.

Datastructures-java-arrays

logic of various problems in arrays.

View on GitHub

Most of the code is in JAVA, but since they are pseudo-codes, you shouldn’t have any difficulties understanding it even if you are using other languages. 😊

If you are learning Datastructures and algorithms, you can star ⭐️ or fork this repository, I'm sure it will help you in the last minute revision!

Since there are a lot of people preparing I thought sharing this will help many aspirants like me who are preparing for interviews or want to improve their DSA skills!

Will be sharing more, as and when I progress.

Keep coding! keep learning! keep growing! 💖

Java: 4 ways to create a String! 💡

Raksha Kannusami — Tue, 01 Sep 2020 13:28:01 +0000

The String Datatype:

A string is nothing but a collection of characters. In java, Strings are immutable. Immutable simply means unmodifiable or unchangeable. Once a string object is created its data or state can't be changed but a new string object is created.

You can create a String using 4 ways in Java:

1. Using a character array

Character Array is a sequential collection of data type char.

char[] array = {'s','t','r','i','n','g'};

2. Using String class

The String class represents character strings. All string literals in Java programs, such as "abc", are implemented as instances of this class. Strings are constant; their values cannot be changed after they are created. String buffers support mutable strings. Because String objects are immutable they can be shared.

String str = "string";

3. Using StringBuffer

A thread-safe, mutable sequence of characters. A string buffer is like a String, but can be modified. At any point in time it contains some particular sequence of characters, but the length and content of the sequence can be changed through certain method calls.
String buffers are safe for use by multiple threads. The methods are synchronized where necessary so that all the operations on any particular instance behave as if they occur in some serial order that is consistent with the order of the method calls made by each of the individual threads involved.

StringBuffer  str = new StringBuffer("string");

4. Using StringBuilder

A mutable sequence of characters. This class provides an API compatible with StringBuffer, but with no guarantee of synchronization. This class is designed for use as a drop-in replacement for StringBuffer in places where the string buffer was being used by a single thread (as is generally the case). Where possible, it is recommended that this class be used in preference to StringBuffer as it will be faster under most implementations.

StringBuilder str = new StringBuilder("string");

Now you know how to create a String, In the upcoming article I will be covering all the String methods that can be used to format Strings.

... To be continued 🎉
keep learning, keep growing 💖

Java: Recursion Basics. 🔁

Raksha Kannusami — Tue, 25 Aug 2020 10:16:15 +0000

What is recursion?

Recursion is a way to write a program where the function calls itself. A function is called recursive if it calls itself directly or indirectly.

When a function calls itself directly:

void function1(){
    .
    . 
    function1();
}

When a function calls itself indirectly:

void function1(){
    .
    .
    function2();
}

void function2(){
    .
    .
    function1();
}

Applications of recursion:

🎯 Dynamic programming
🎯 Backtracking
🎯 Searching algorithms like Binary search
🎯 Sorting algorithms like merge sort and quick sort
🎯 Tree traversals ... etc.

Is recursion better than iteration?

Even though recursion might look like its better than iteration since the length of the code is less, it is the iteration that is always efficient when it comes to the time complexity of the code. This is because, when recursive code is being compiled, the number of arguments in the function call stack increases and this increases the time complexity of the code.

Printing 1 to N using Recursion

class Test{
  static void print1toN(int n)
  {
    if(n==0)
      return;
    print1toN(n-1);
    System.out.print(n+" ");
}

public static void main(String[] args)
{
  int n=10;
  print1toN(n);
}
}

Printing N to 1 using Recursion

class test{
  static void printNto1(int n)
  {
    if(n==0)
      return;

    System.out.print(n+" ");
    printNto1(n-1);
  }
}

public static void main(String args[])
{
  int n=10;
  PrintNto1(n);
}

Some Recursive problems to explore:

Basic Problems:

Fibonacci series using recursion
Sum of natural numbers using recursion
Palindrome check using recursion
Sum of digits using recursion

Advanced Problems:

Tower of Hanoi
Rod cutting problem
Josephus problem

To get good at recursion, practice is the key. After a significant amount of practice, you'll easily recognize the questions that you can solve using recursion!

To start off, you can practice the above-listed problems on GeeksforGeeks or Leetcode. 👩🏻‍💻

... to be continued 🎉

keep learning, keep coding! 🌸

Java: Wrapper Class ⭐️

Raksha Kannusami — Tue, 18 Aug 2020 17:20:54 +0000

🔰 what is a wrapper class in Java?

A Wrapper class is a class whose object wraps or contains primitive data types. When we create an object to a wrapper class, it contains a field and in this field, we can store primitive data types. In other words, we can wrap a primitive value into a wrapper class object.

🔰 Why do we need a Wrapper class?

They convert primitive data types into objects. Objects are needed if we wish to modify the arguments passed into a method (because primitive types are passed by value).
The classes in java.util package handles only objects and hence wrapper classes help in this case also.
Data structures in the Collection framework, such as ArrayList and Vector, store only objects (reference types) and not primitive types.
An object is needed to support synchronization in multithreading.

🔰 How to create a wrapper class for primitive data types?

// primitive data type - Wrapper Class
   char                - Character
   byte                - Byte
   short               - Short
   int                 - Integer
   long                - Long
   float               - Float
   double              - Double
   boolean             - Boolean

How to create a Wrapper class?

Let us see an example of how to create a wrapper class below.

class autoBoxing{
  public static void main(String[] args){
    char ch = 'a';

    //converting primitive data type into an object (autoboxing)
    Character a = ch;
  }
}

The above process is also called as Autoboxing.

🔰 Autoboxing:

Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes. For example, converting an int to an Integer, a double to a Double, and so on. If the conversion goes the other way, this is called unboxing.

...To be continued. 🎉

keep learning, Keep coding. 💖

Productivity: Are you a fox 🦊 or a hedgehog 🦔?

Raksha Kannusami — Tue, 11 Aug 2020 16:24:26 +0000

Disclaimer:

This is a short story that I came across that really intrigued me and want to share it with you all. By the end of this article, I encourage you all to get insights from this post, that will help you with your coding journey.

Ask yourself:

before we dive into the story, ask this question to yourself.
If you were given a chance to be a fox 🦊 or hedgehog 🦔, which one would you chose?

Obviously the FOX! 🦊
Fox is so beautiful, sleek, and cunning. On the other hand, Hedgehogs are slow, timid, and not so interesting.

Read this story:

The fox is a cunning creature, able to devise a myriad of complex strategies for sneak attacks upon the hedgehog. Every day, the fox circles around the hedgehog’s den, waiting for the perfect moment to pounce. Fast and crafty—the fox looks like the sure winner. The hedgehog, on the other hand, waddles along, going about his simple day, searching for lunch, and taking care of his home.

The fox waits in cunning silence at the juncture in the trail. The hedgehog, minding his own business, wanders right into the path of the fox. “Aha, I’ve got you now!” thinks the fox. He leaps out, bounding across the ground, lightning-fast. The little hedgehog, sensing danger, looks up and thinks, “Here we go again. Will, he ever learn?” Rolling up into a perfect little ball, the hedgehog becomes a sphere of sharp spikes, pointing outward in all directions.

The fox, bounding toward his prey, sees the hedgehog defense and calls off the attack. Retreating back to the forest, the fox begins to calculate a new line of attack. Each day, some version of this battle between the hedgehog and the fox takes place, and despite the greater cunning of the fox, the hedgehog always wins.

Moral:

🦊 The FOX

Foxes pursue many ends at the same time and see the world in all its complexity. They are scattered or diffused, moving on many levels never integrating their thinking into one overall concept or unifying vision.

🦔 The Hedgehog

Hedgehogs, on the other hand, simplify a complex world into a single organizing idea, a basic principle or concept that unifies and guides everything. It doesn’t matter how complex the world, a hedgehog reduces all challenges and dilemmas to simple—indeed almost simplistic— hedgehog ideas. For a hedgehog, anything that does not somehow relate to the hedgehog idea holds no relevance.

Ask yourself again.

Am I a fox 🦊 or a hedgehog 🦔 ?
My thoughts are fox-like or hedgehog-like?

Conclusion:

The hedgehog, despite the fox's cleverness, does one thing imperially well — it knows how to defend itself. If a hedgehog and fox were to compete, the hedgehog would be the fairer. But taken figuratively, hedgehog thinking draws from a central vision and foxes search for seemingly unrelated or even contradictory pursuits. The origin of the "fox or hedgehog" concept is unclear, and interpretations have changed over the years.

Princeton professor Marvin Bressler pointed out the power of the hedgehog and said: “You want to know what separates those who make the biggest impact from all the others who are just as smart? They’re hedgehogs.”

The take-backs:

Don't try to do a lot of things at once.
Don't get distracted.
Be the master of one, rather than a jack of all trades.
Don't compare yourself.

Are you ready to be a hedgehog, mark your goals, and smash them?

keep learning, keep coding, keep growing. 🌸

#100DaysOfCode challenge!

Raksha Kannusami — Tue, 04 Aug 2020 04:07:10 +0000

🧐 what is the #100DaysOfCode challenge?

It is a challenge that you take up for the next 100 days where you follow the 2 simple rules below.

Code for a minimum of one hour a day.
Tweet your progress with the hashtag #100DaysofCode.

🤔 Who can take up this challenge?

To be short and precise, anyone who wants to learn to code/ improve their coding skills. In this challenge, you may learn any programming language, work on a project, or even read books and code. The only thing to be kept in mind is that, make sure you are learning and gaining something every day for the next 100 days.

❓ Why did I take up this challenge?

I started studying Datastructures and Algorithms 2 months back but eventually lost my motivation. I wanted something that would give me the push every day to sit and learn.

👨🏻‍💻 Why tweet your progress?

Twitter has an amazing community for software developers just like the DEV community. People are friendly and welcoming and you can easily find like-minded people.

Raksha Kannusami

@kannusamiraksha

I'm officially starting with #100DaysOfCode. My main aim in the upcoming 100 days will be to learn DSA! Wish me luck! 🌻

03:49 AM - 31 Jul 2020

It's been four days since I started this challenge and have had great encouragement from the community. Hope to come back after 100 days and update you all about my learnings from those 100 days. Wish me luck. 🤞🏽

🔰 Know more about the challenge:

You can learn more about the challenge from the official website.
Keep learning! Keep coding! 💖

🎉 Update:

I have completed the challenge successfully!
Definitely was not easy to be consistent at the beginning, but eventually fell in love with the community support.

Java: Arrays!

Raksha Kannusami — Tue, 28 Jul 2020 07:53:43 +0000

Most interviews for an SDE (software development engineer) role require you to have a good grasp of Data structures and algorithms.

One important data structure is Arrays.

An array is a linear data structure and is famous for storing values at contiguous memory locations.

This article will help you to get started with arrays. 🥳

I will be using Java, but don't worry, you should be able to understand these pseudo-codes irrespective of programming language.

Let us understand the basic manipulation on arrays like insert, delete, sort, etc.

1. Create an array.

To create an integer array of size 100,

int[] array = new int[100];

2. Insert an element into an array.

The following function will insert any element at any position specified by the user and will return the size of the modified array after insertion.

int insert(int array[], int n, int x, int capacity, int position)
{
  if(n==capacity)
    return n; //cannot insert any element since exceeding capacity
  int index = position-1;
  for(int i=n-1; i>=index;i--)
    array[i+1]=array[i];
  array[index]=x;
  return (n+1); //returns the size of the new array.
}

3. Delete an element from an array.

The following function will delete any element at the position specified by the user and will return the size of the modified array after deletion.

int delete(int array[],int n, int x)
{
  int i;
  for(int i=0;i<n;i++)
    if(array[i]==x)
      break;
    if (i==n)
      return n; // the element is not present in the array
    for(int j=i;j<n-1;j++)
      array[j]=array[j+1];
    return (n-1); // returns the size of array after deletion
}

4. Sort an array (Ascending order).

Java has an arrays class which can be used to sort arrays by importing java.util.Arrays.

Arrays.sort(array);

These were the basic manipulation of arrays that can get you started with. If you want to dive deeper and master them to crack technical interviews, then try to build your logic to solve the following questions:

-> How to reverse an array?
-> How to find leaders in an array?
-> How to left rotate an array?
-> What is kadane's algorithm?
-> What is the sliding window technique?
-> How to solve the Trapping rainwater problem?
-> How to remove duplicate elements in an array?
-> How to find subarrays for a given condition?

If you can explore the above-listed problems and as well as solve the questions on your favorite coding platform, that should give you enough confidence to crack any type of coding question based on arrays. 🎉

To get started with, try Hackerrank or Hackerearth. 👩🏻‍💻

Happy learning! happy coding! 💖

Java: The datatypes. {}

Raksha Kannusami — Wed, 22 Jul 2020 10:36:46 +0000

🎯 What is a data type?

Wikipedia says "In computer science and computer programming, a data type or simply type is an attribute of data which tells the compiler or interpreter how the programmer intends to use the data. Most programming languages support basic data types of integer numbers (of varying sizes), Floating-point numbers (which approximate real numbers), characters, and Booleans. A data type constrains the values that an expression, such as a variable or a function, might take. This data type defines the operations that can be done on the data, the meaning of the data, and the way values of that type can be stored. A data type provides a set of values from which an expression (i.e. variable, function, etc.) may take its values."

🎯 Types:

There are 2 types of data types in Java: Primitive and Non-Primitive. In simple words, primitive data types are predefined whereas non-primitive data types are user defined.

🎯 Primitive Datatypes:

A primitive data type specifies the size and type of variable values and has no additional methods. There are 8 primitive data types in Java: byte, short, int, long, float, double, boolean, char. Let us see how to initialize them below.

Byte

byte x=10;

Short

short x=10;

Int

int x=10;

Long

long x=10000000;

Float

float x=10f;

Double

double x=10.1010;

Boolean

boolean x=1;

Char

char c ='s';

🎯 Non-Primitive Datatypes:

Non-primitive data types are called reference types because they refer to objects. There are many non-primitive data types in Java: arrays, strings, classes etc. Let us see how to initialize an array and a string.

Array

int[] array = new int[10];

String

String s = "hello world";

Since now we know what data types are, it is important to learn the usage of these data types so that we know where to use them to solve a problem.

...To be continued! 🎉
keep learning, keep coding!💖