二路归并排序

#include<iostream>
using namespace std;
void merge(int a[], int low, int mid, int high)
{
	int n1 = mid-low + 1;
	int n2 = high - mid;
	int* L = (int*)malloc(sizeof(int)*n1);
	int* R = (int*)malloc(sizeof(int)*n2);
	int i, j, k;
	for (i = 0, k = low; i < n1; i++, k++)
		L[i] = a[k];
	for (j = 0, k = mid + 1; j < n2; j++, k++)
		R[j] = a[k];//数组复制完成
	for (i = 0, j = 0, k = low; i < n1 && j < n2; k++)
	{
		if (L[i] < R[j])
		{
			a[k] = L[i];
			i++;
		}
		else
		{
			a[k] = R[j];
			j++;
		}
	}
	while (i < n1)
	{
		a[k] = L[i];
		i++, k++;
	}
	while (j < n2)
	{
		a[k] = R[j];
		j++, k++;
	}
}
void mergesort(int a[], int low, int high)
{
	if (low < high)
	{
		int mid = (low + high) / 2;
		mergesort(a, low, mid);
		mergesort(a, mid + 1, high);
		merge(a, low, mid, high);
	}
}
int main()
{
	int arr[8] = { 10,8,5,0,45,12,74,56 };
	cout << "归并排序之后的:" << endl;
	mergesort(arr, 0, 7);
	for (int i = 0; i < 8; i++)
	{
		cout << arr[i]<<" ";
	}
	return 0;
}