Shell排序未对数组的第一个元素进行排序

Question

When my sort is run on this data {7,8,4,2,3,9,5,8,4,1} only the first element is not put in its correct place. How can I fix this? Thanks for the help.

public void segmentedInsertionSort(int[] array, int size, int h)
    {
        int temp;

        for(int i = h + 1 ;i < size;i++)
        {
            int j = i - h;


            while(j > 0)
            {
                if(array[j+h] < array[j])
                {
                    temp = array[j];
                    array[j] = array[j+h];
                    array[j+h] = temp;
                    j = j - h;
                }
                else
                {
                    j = 0;
                }
            }
        }
    }

    public void shellSort(int[] array, int size)
    {
        int h = size/2;

        while(h > 0)
        {
            segmentedInsertionSort(array,size,h);
            h = h/2;
        }            
    }

Answer 1

for(int i = h + 1 ;i < size;i++)
        {
            int j = i - h;


            while(j > 0)
            {
                if(array[j+h] < array[j])
                {
                    temp = array[j];
                    array[j] = array[j+h];
                    array[j+h] = temp;
                    j = j - h;
                }

In this part, you define i = h + 1 and then increase i value. So, so the j value is never less than 1 when the sort runs. Therefore, it never processes the first element of array. You need to fix this part.

Answer 2

I think you have misvalued some variables.Your variable j never reaches index 0 so as to compare 7 with any other value in this Comparison Sort.

Change:

for(int i = h +1 ;i < size;i++) to for(int i = h ;i < size;i++)

And

while(j > 0) to while(j >= 0)

else { j = 0; }

to else{ j = -1; } else{ j = -1; }

Final Code looks like:

` void segmentedInsertionSort(int arr[], int size, int h)
{
    int temp;

    for(int i = h  ;i < size;i++)
    {
        int j = i-h ;


        while(j >= 0)
        {
            if(arr[j+h] < arr[j])
            {
                temp = arr[j];
                arr[j] = arr[j+h];
                arr[j+h] = temp;
                j = j - h;
            }
            else
            {
                j = -1;
            }
        }
    }
}
void shellSort(int arr[], int size)
{
    int h = size/2;

    while(h > 0)
    {
        print(arr);
        segmentedInsertionSort(arr,size,h);
        h = h/2;
    }            
}