I try to make the merge sort go from bigger to little but it keep going from little to big

Question

Trying to get it from big to little I'm trying to use the Sort & Search Merge Sort:

import java.util.*;

class MergeSorter {
   public static void sort(int[] a) {  
      if (a.length <= 1) { return; }
      int[] first = new int[a.length / 2];
      int[] second = new int[a.length - first.length];
      for (int i = 0; i < first.length; i++) { 
         first[i] = a[i]; 
      }
      for (int i = 0; i < second.length; i++) { 
         second[i] = a[first.length + i]; 
      }
      sort(first);
      sort(second);
      merge(first, second, a);
   }

   private static void merge(int[] first, int[] second, int[] a) {  
      int iFirst = 0;
      int iSecond = 0;
      int j = 0;

      while (iFirst < first.length && iSecond < second.length) {  
         if (first[iFirst] < second[iSecond]) {  
            a[j] = first[iFirst];
            iFirst++;
         } else {  
            a[j] = second[iSecond];
            iSecond++;
         }
         j++;
      }
      while (iFirst < first.length) { 
         a[j] = first[iFirst]; 
         iFirst++; j++;
      }
      while (iSecond < second.length) { 
         a[j] = second[iSecond]; 
         iSecond++; j++;
      }
   }
}

public class MergeSortDemo888888 {
   public static void main(String[] args) {
      int [] myAry = { 3, 2, 6, 7 };
      System.out.println("myAry is " + Arrays.toString(myAry));
      MergeSorter.sort(myAry);
      System.out.println("myAry is sorted descendingly using selection sort: "+Arrays.toString(myAry));
   }
}

Try to dry run the code on the array you have chosen as example and see why it is sorting from little to big. Have a closer look at the `merge` function. Some reference to help: https://www.geeksforgeeks.org/merge-sort/ — Nikhil Sahu, Apr 26 '20 at 08:43

score 1 · Accepted Answer · answered Apr 25 '20 at 21:10

1

In the first if in the merge function just change this (first[iFirst] < second[iSecond]) into this (first[iFirst] > second[iSecond]).

answered Apr 25 '20 at 21:10

Alberto Ursino

366
3
18

OMG thanks alot im a new to coding and this had me going crazy – RegularDotSquare Apr 25 '20 at 21:17
hey it you dont mind looking at my second question having a problem with it – RegularDotSquare Apr 25 '20 at 22:23
Where's your 2nd question? – Alberto Ursino Apr 25 '20 at 23:35
using the LinkedList Decare a number n = 1279. 4. The sample output: The number is 1729 1, 7, 2, 9, – RegularDotSquare Apr 25 '20 at 23:58

I try to make the merge sort go from bigger to little but it keep going from little to big

1 Answers1