我正在为我的CS类进行非递归合并排序,它不完全正常工作。我知道它被调用,因为当我运行测试程序时,它会改变数组,只是没有按照正确的顺序。有人可以帮忙吗?谢谢!非递归合并排序Java
private static void mergeSort(int[] a, int left, int right)
{
int midPoint = ((right + left)/2);
int[] buffer = new int[19];
selectionSort(a, left, midPoint);
selectionSort(a, midPoint-1, right);
merge(a, buffer, 0, 9, 19);
}
private static void selectionSort(int[] a, int beginning, int end)
{
int [] temp = new int[end-1];
for(int y = 0; y < end - 1; y++)
{
temp[y] = a[y];
}
for (int i = 0; i < temp.length - 1; i++)
{
int minIndex = findMinimum(temp, i);
if (minIndex != i)
swap (temp, i, minIndex);
}
}
private static int findMinimum(int[] a, int first)
{
int minIndex = first;
for (int i = first + 1; i < a.length; i++)
{
if (a[i] < a[minIndex])
minIndex = i;
}
return minIndex;
}
private static void swap(int []a, int x, int y)
{
int temp = a[x];
a[x] = a[y];
a[y] = temp;
}
private static void merge(int[] a, int[] temp, int left, int mid, int right) {
if (mid >= a.length) return;
if (right > a.length) right = a.length;
int i = left, j = mid+1;
for (int k = left; k < right; k++) {
if (i == mid)
temp[k] = a[j++];
else if (j == right)
temp[k] = a[i++];
else if (a[j] < a[i])
temp[k] = a[j++];
else
temp[k] = a[i++];
}
for (int k = left; k < right; k++)
a[k] = temp[k];
}
为什么在调用'selectionSort'时使用参数'left'和'right',中点'midPoint' - 调用'merge'时使用硬连线常量?为什么你硬连线'buffer'的长度 - 为什么不'int [] buffer = new int [a.length]'? – ajb
我手动连接它们以确保参数具有正确的值,并且忘记将它们作为参数 – user3266115