Question

Given an array a0, a1 ,a2,....an-2, an-1, call function Rearrange to rearrange the

array elements so that the new arranged array is: a0, an-1 ,a1, an-2......

If the array was

5,7,13,4,9

Then after calling function Rearrange Array elements are: 5, 9, 7, 4, 13

in java

Answer 1

// Java program to create and test rearrange method

public class Rearrange {

       // method to rearrange the array elements

       public static void rearrange(int array[])

       {

             int temp[] = new int[array.length]; // create a temporary array of same length as input array

             int i=0, j=0; // set i and j to start index

             // loop that continues till we reach middle of the array

             while(i<array.length/2)

             {

                    temp[j] = array[i]; // set ith element of array to jth element of temp

                    j++; // increment j

                    temp[j] = array[array.length-1-i]; // set ith element from last of array to jth element of temp

                    j++; // increment j

                    i++; // increment i

             }

            

             // if array contains odd elements , copy the middle element of array to temp

             if(array.length%2 != 0)

             {

                    temp[j] = array[array.length/2];

             }

            

             // copy the element from temp back to array

             for(i=0;i<array.length;i++)

             {

                    array[i] = temp[i];

             }

            

       }

       public static void main(String[] args) {

      

             // test the method

             int arr[] = {5,7,13,4,9};

             int arr1[] = {5,7,13,4,9,10};

            

             System.out.println("Before : "+Arrays.toString(arr));

             rearrange(arr);

             System.out.println("After rearrange : "+Arrays.toString(arr));

             System.out.println("Before : "+Arrays.toString(arr1));

             rearrange(arr1);

             System.out.println("After rearrange : "+Arrays.toString(arr1));

               }

}

//end of program

Output: