我尝试使合并排序从大到小，但它一直从小到大

Question

试图从大变小我正在尝试使用排序和搜索合并排序：

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));
   }
}

Answer 1

在 merge 函数的第一个 if 中，只需将此 (first[iFirst] < second[iSecond]) 更改为此 (first[iFirst] > second[iSecond])。

我尝试使合并排序从大到小，但它一直从小到大

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

java

mergesort

helper

jgrasp