Question

JAVA please write this method

public static void recursiveMergeSort(int[] arr) {

}

Answer 1

class MergeSort { 
  public static void merge(int[] result, int[] first, int[] second)      
   {
      int i, j, k;
      i = j = k = 0;
      //while till both completly copied
      while ( i < first.length || j < second.length )
      {
         if ( i < first.length && j < second.length )
         {  
             //compate element
            if ( first[i] < second[j] )
               result[k++] = first[i++];
            else
               result[k++] = second[j++];
         }
         else if ( i == first.length )
            result[k++] = second[j++];   //while first completed then 2nd copy 
         else if ( j == second.length )
            result[k++] = first[i++];     //while second completed then 1st copy 
      }
   }
  
    public static void recursiveMergeSort(int[] arr)
   {
      int[] Arrayleft, Arrayright;
 // if array consist 1 element
      if ( arr.length == 1 )
      {
         return;
      }
      int midindex = arr.length/2;//get mid index
      Arrayleft  = new int[midindex]; //array to hold left part
      for ( int i = 0; i < midindex; i++ )
         Arrayleft[i] = arr[i];//copy elements
      Arrayright = new int[arr.length-midindex];  //array to hold right part
      for ( int i = 0; i < arr.length-midindex; i++ )
         Arrayright[i] = arr[i+midindex];//copy elements
      recursiveMergeSort( Arrayleft );     //call recusively
      recursiveMergeSort( Arrayright );     //call recusively
      merge( arr, Arrayleft, Arrayright );  //Merge left and right array
   }
    static void DisplayArray(int array[]) 
    { 
        int size = array.length; 
        for (int i = 0; i < size; ++i) 
            System.out.print(array[i] + " "); 
        System.out.println(); 
    } 
  
    // Driver method 
    public static void main(String args[]) 
    { 
        int array[] = { 4,8,52,41,14,96,7 }; 
  
        System.out.println("Original Array"); 
        DisplayArray(array); 
        recursiveMergeSort(array); 
        System.out.println("Sorted Array"); 
        DisplayArray(array); 
    } 
} 

/*

Output

Original Array
4 8 52 41 14 96 7
Sorted Array
4 7 8 14 41 52 96

*/