11.2 对数组归并排序

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#define LEN 8
int a[LEN] = { 5,2,4,7,1,3,2,6 };
void merge(int start, int mid, int end)
{
int n1 = mid - start + 1;
int n2 = end - mid;
int left[LEN], right[LEN];
int i, j, k;
for (i = 0;i < n1;i++)
left[i] = a[start + i];
for (j = 0;j < n2;j++)
right[j] = a[mid + 1 + j];
i = j = 0;
k = start;
while (i < n1&&j < n2)
if (left[i] < right[j])
a[k++] = left[i++];
else
a[k++] = right[j++];
while (i < n1)
a[k++] = left[i++];
while (j < n2)
a[k++] = right[j++];
}
void sort(int start, int end)
{
int mid;
if (start < end)
{
mid = (start + end) / 2;
printf("sort (%d-%d,%d-%d) to %d %d %d %d %d %d %d %d \n", start, mid, mid + 1, end, a[0],a[1], a[2], a[3], a[4], a[5], a[6], a[7]);
sort(start, mid);
sort(mid + 1, end);
merge(start, mid, end);
printf("merge(%d-%d,%d-%d) to %d %d %d %d %d %d %d %d ", start, mid, mid + 1, end, a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7]);
printf("\n");
}
}
int main(void)
{
sort(0, LEN - 1);
getchar();
return 0;
}