归并排序（递归）

#include<iostream>
using namespace std;
void Merge(int arr[], int low, int mid, int high)
{
	int i = low;
	int j = mid + 1;
	int k = 0;
	int *temp = new int[high - low + 1];
	if (!temp)
	{
		cout << "ERROR!" << endl;
	}
	while (i <= mid&&j <= high)
	{
		if (arr[i] <= arr[j])
			temp[k++] = arr[i++];
		else
			temp[k++] = arr[j++];
	}
	while (i <= mid) temp[k++] = arr[i++];
	while (j <= high) temp[k++] = arr[j++];
	for (int i = low, k = 0; i <= high; i++, k++)
		arr[i] = temp[k];
	delete[]temp;
}
void MergeSort(int arr[], int low, int high)
{
	if (low < high)
	{
		int mid = (low + high) / 2;
		MergeSort(arr, low, mid);
		MergeSort(arr, mid + 1, high);
		Merge(arr, low, mid, high);
	}
}
int main()
{
	int arr[] = { 10,9,8,7,6,5,4,3,2,1 };
	MergeSort(arr, 0, 9);
	for (int i = 0; i <= 9; i++)
	{
		cout << arr[i] << " ";
	}
	return 0;
}