Three way partitioning Java

PROGRAM TO PARTITION AN ARRAY AROUND A GIVEN RANGE

Given an array and a range [lowVal, highVal], partition the array around the range such that array is divided in three parts.
1) All elements smaller than lowVal come first.
2) All elements in range lowVal to highVVal come next.
3) All elements greater than highVVal appear in the end.
The individual elements of three sets can appear in any order.

import java.io.*;

  

class MAIN

{

      

    // Partitions arr[0..n-1] around [lowVal..highVal]

    public static void threeWayPartition(int[] arr, int lowVal, int highVal)

    {

          

        int  n = arr.length;

          

        // Initialize ext available positions for

        // smaller (than range) and greater lements

        int start = 0, end = n-1;

          

         // Traverse elements from left

        for(int i = 0; i <= end;)

        {

              

            // If current element is smaller than

            // range, put it on next available smaller

            // position.

              

            if(arr[i] < lowVal)

            {

                  

                int temp = arr[start];

                arr[start] = arr[i];

                arr[i] = temp;

                start++;

                i++;

                  

            }

              

            // If current element is greater than

            // range, put it on next available greater

            // position.

            else if(arr[i] > highVal)

            {

                  

                int temp = arr[end];

                arr[end] = arr[i];

                arr[i] = temp;

                end--;

                   

            }

              

            else

               i++;

        }

          

    }

      

    public static void main (String[] args) 

    {

      

      

        int arr[] = {1, 14, 5, 20, 4, 2, 54, 20, 87, 98, 3, 1, 32};

          

        threeWayPartition(arr, 10, 20);

   

        System.out.println("Modified array ");

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

        {

            System.out.print(arr[i] + " ");

      

        }    

    }

}

OUTPUT

Modified array 
1 5 4 2 1 3 14 20 20 98 87 32 54 

CREDITS: https://www.geeksforgeeks.org/three-way-partitioning-of-an-array-around-a-given-range/