java中使用MergeSorter的问题

我正在研究这个合并分拣机，但有一些东西不起作用，我无法弄清楚。感谢您的帮助。非常感谢。问题很可能出在排序方法中

public class MergeSorter
{
private int[] a;

/**
  Constructs a merge sorter.
  @param anArray the array to sort
*/
public MergeSorter(int[] anArray)
{
  a = anArray;
}

/**
  Sorts the array managed by this merge sorter.
*/
public void sort()
{
  int size = 1;
  int from = 0;
  int to = a.length - 1;

  // Complete this for the draft
  while (size < to - from)
  {
     for (int i = 0; i<=a.length; i=i+size*2) //for (int i = 0; i<a.length; i=i+size*2)
     {
         if(a.length>i+size*2-1){
             merge(i, i+size-1, i+size*2-1);
         }
         else if(a.length>i+size){
             merge(i, i+size-1, a.length-1);

         }
     }
     size = 2 * size;
  }
}

public void merge(int from, int mid, int to)
{
  System.out.println("Merging " + from + "..." + mid
 + " and " + (mid + 1) + "..." + to);

  // Complete this method for the final submission
  int iFirst = from; // Next element to consider in the first array
  int iSecond = mid+1; // Next element to consider in the second array
  int temp = 0;

  // As long as neither iFirst nor iSecond is past the end, move
  // the smaller element into a
  while (iFirst <= mid && iSecond <= to)
  {
     if (a[iFirst] < a[iSecond])
     {
        iFirst++;
     }
     else if (a[iFirst] > a[iSecond])
     {
        temp = a[iFirst];
        a[iFirst] = a[iSecond];
        a[iSecond] = temp;
        iSecond++;
     }
  }
}
}

这是输出，但问题是最后一行的数字不是连续的

 Merging 0...0 and 1...1
 Merging 2...2 and 3...3
 Merging 4...4 and 5...5
 Merging 6...6 and 7...7
 Merging 8...8 and 9...9
 Merging 10...10 and 11...11
 Merging 12...12 and 13...13
 Merging 14...14 and 15...15
 Merging 16...16 and 17...17
 Merging 18...18 and 19...19
 Merging 0...1 and 2...3
 Merging 4...5 and 6...7
 Merging 8...9 and 10...11
 Merging 12...13 and 14...15
 Merging 16...17 and 18...19
 Merging 0...3 and 4...7
 Merging 8...11 and 12...15
 Merging 0...7 and 8...15
 Merging 0...15 and 16...19
 0 1 2 3 4 5 6 7 8 9 12 13 14 15 16 17 10 11 18 19 Press any key to continue . .

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谢谢你的帮助。谢谢

合并方法中有一个错误。检查以下示例。

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使用参数merge（0,2,4）和a={5,6,7,1,2}运行方法merge。您将得到a={1,2,7,5,6}。

合并方法中有一个错误。检查以下示例。 使用参数merge（0,2,4）和a={5,6,7,1,2}运行方法merge。您将得到a={1,2,7,5,6}

 Merging 0...0 and 1...1
 Merging 2...2 and 3...3
 Merging 4...4 and 5...5
 Merging 6...6 and 7...7
 Merging 8...8 and 9...9
 Merging 10...10 and 11...11
 Merging 12...12 and 13...13
 Merging 14...14 and 15...15
 Merging 16...16 and 17...17
 Merging 18...18 and 19...19
 Merging 0...1 and 2...3
 Merging 4...5 and 6...7
 Merging 8...9 and 10...11
 Merging 12...13 and 14...15
 Merging 16...17 and 18...19
 Merging 0...3 and 4...7
 Merging 8...11 and 12...15
 Merging 0...7 and 8...15
 Merging 0...15 and 16...19
 0 1 2 3 4 5 6 7 8 9 12 13 14 15 16 17 10 11 18 19 Press any key to continue . .