Scala – Page 2 – Clear ur Doubt

Dec 06

Printing Fibonacci series in Scala – Normal Recursion

Hey there! Welcome to ClearUrDoubt.com. In this post, we will look at a Scala program to print Fibonacci series using simple Recursion. Fibonacci Series: Finding n’th element: f(n) = f(n-1) + f(n-2)

package com.clearurdoubt

object Fibonacci extends App {

  def fibonacci(n: Int): List[Int] = {
    def fibonacci(a: Int, b: Int): LazyList[Int] = a #:: fibonacci(b, a+b)

    fibonacci(0,1).take(n).toList
  }

  fibonacci(10)
}

package com.clearurdoubt

object Fibonacci extends App {

def fibonacci(n: Int): List[Int] = {

def fibonacci(a: Int, b: Int): LazyList[Int] = a #:: fibonacci(b, a+b)

fibonacci(0,1).take(n).toList

}

fibonacci(10)

}

Output: Happy learning. Please leave a reply Read more

Nov 30

Merge Sort implementation in Scala

Hey there! Welcome to ClearUrDoubt.com. In this post, we will look at a Scala program to implement merge sort. Merge Sort is an efficient sorting algorithm. It uses Divide and Conquer algorithm technique. Let’s look at the sample program:

package com.clearurdoubt

/**  
 * Merge Sort is a divide and conquer algorithm.
 * 
 * We have to divide the initial list into two halves and sort those lists and merge them once they are sorted. *  
 */
object MergeSort extends App {
  
  def mergeSort(input: List[Int]) : List[Int] = {
    
    val middle = input.length / 2
    
    if(middle == 0) input
    else {
      def merge(xs: List[Int], ys: List[Int]): List[Int] = (xs, ys) match {
        case (Nil, ys) => ys
        case (xs, Nil) => xs
        case (x :: xs1, y :: ys1) => 
          if (x < y)               
            x :: merge(xs1, ys)    // append x and merge(remaining elements of xs (i.e., xs1), ys) 
          else 
            y :: merge(xs, ys1)    // append y and merge(xs , remaining elements of ys (i.e., ys1)) 
      }
      
      val (left, right) = input splitAt middle   // Split the list into two halves
      merge(mergeSort(left), mergeSort(right))   // Apply merge on the sorted halves 
    }
  }
  
  val numbers = List(2, -4, 4, 6, 1)
  
  println("Input:    " + numbers)
  println("Reversed: " + mergeSort(numbers))
}

package com.clearurdoubt

/**

* Merge Sort is a divide and conquer algorithm.

* We have to divide the initial list into two halves and sort those lists and merge them once they are sorted. *

object MergeSort extends App {

def mergeSort(input: List[Int]) : List[Int] = {

val middle = input.length / 2

if(middle == 0) input

else {

def merge(xs: List[Int], ys: List[Int]): List[Int] = (xs, ys) match {

case (Nil, ys) => ys

case (xs, Nil) => xs

case (x :: xs1, y :: ys1) =>

if (x < y)

x :: merge(xs1, ys) // append x and merge(remaining elements of xs (i.e., xs1), ys)

else

y :: merge(xs, ys1) // append y and merge(xs , remaining elements of ys (i.e., ys1))

}

val (left, right) = input splitAt middle // Split the list into two halves

merge(mergeSort(left), mergeSort(right)) // Apply merge on the sorted halves

}

val numbers = List(2, -4, 4, 6, 1)

println("Input: " + numbers)

println("Reversed: " + mergeSort(numbers))

}

Nov 29

How to reverse a List elements without using utility method in Scala

Hey there! Welcome to ClearUrDoubt.com. In this post, we will look at a simple program to reverse a List of elements without using utility method(reverse) in Scala. Let’s look at the program:

package com.clearurdoubt

object Reversing {
  
  def main(args: Array[String]) {
    val list = List(3,4,5,1,2,3) 
    val rev = reversed(list)
    
    println(rev + " @@ " + list.reverse)
  }
  
  def reversed(input: List[Int]): List[Int] = input match {    
    case List() => input
    case x :: xs => reversed(xs) ::: List(x)
  }   
}

package com.clearurdoubt

object Reversing {

def main(args: Array[String]) {

val list = List(3,4,5,1,2,3)

val rev = reversed(list)

println(rev + " @@ " + list.reverse)

}

def reversed(input: List[Int]): List[Int] = input match {

case List() => input

case x :: xs => reversed(xs) ::: List(x)

}

Output: Happy Learning. Please leave a reply Read more

Nov 14

Scala program to find Factorial of a given number using Tail Recursion

Hey there! Welcome to ClearUrDoubt.com. In this post, we will look at a Scala program to find Factorial of a given number using Tail Recursion. Tail Recursion: If a function calls itself as the last action in the definition, it Read more

Nov 14

Scala program to find Factorial of a given number

Hey there! Welcome to ClearUrDoubt.com. In this post, we will look at a Scala program to find Factorial of a given number using Linear Recursion. Let’s look at the program:

package com.clearurdoubt

object Factorial extends App {
  def factorial(n: Int) : Int = {
    if (n == 0) 1
    else n * factorial(n-1)  // Linear Recursion
  }

  println(factorial(10))
 }

package com.clearurdoubt

object Factorial extends App {

def factorial(n: Int) : Int = {

if (n == 0) 1

else n * factorial(n-1) // Linear Recursion

}

println(factorial(10))

}

Output: Currently this program uses Linear Recursion for finding Read more

Nov 02

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Category: Scala

Printing Fibonacci series in Scala – Normal Recursion

Merge Sort implementation in Scala

How to reverse a List elements without using utility method in Scala

Scala program to find Factorial of a given number using Tail Recursion

Scala program to find Factorial of a given number

How to add multiple elements to a Set object in Scala

How to remove duplicates from an Array in Scala

Sorting a List of custom objects using sortWith function in Scala