归并排序

#include <stdio.h>

void merge_array(int arr[],int begin, int mid, int end);
void print_array(int arr[], int len);
void merge_sort(int arr[], int begin, int end);

void main(void)
{
	int array[8] = {2, 5, 4, 7, 1, 3, 2, 6};

	merge_sort(array, 1, 8);
	print_array(array, 8);   
}

void merge_array(int arr[], int begin, int mid, int end)
{
	int i, j, k;
	int left_arr_len = mid - begin + 1;
	int right_arr_len = end - mid;
	int left_array[left_arr_len + 1];
	int right_array[right_arr_len + 1];

	for (i = 0; i < left_arr_len; i++)
	{
		left_array[i] = arr[begin+i-1];
	}

	for (j = 0; j < right_arr_len; j++)
	{
		right_array[j] = arr[mid+j];
	}

	left_array[left_arr_len] = 1000;
	right_array[right_arr_len] = 1000;

	for (k = begin, i = 0, j = 0; k < end+1; k++)
	{
		if (left_array[i] <= right_array[j])
		{
			arr[k-1] = left_array[i];
			i++;
		}
		else
		{
			arr[k-1] = right_array[j];
			j++;
		}
	} 
}

void merge_sort(int arr[], int begin, int end)
{
	int mid;

	if (begin < end)
	{
		mid = (begin + end) / 2;
		merge_sort(arr, begin, mid);
		merge_sort(arr, mid + 1, end);
		merge_array(arr, begin, mid, end);	
	}    
}

void print_array(int arr[], int len)
{
	int i;

	for (i = 0; i < len; i++)
	{
		printf("%d ", arr[i]);
	}
	printf("\n");
}