归并排序

void Merg(datatype a[], int n,datatype swap[],int k) {      //归并排序
	int m = 0, u1, u2, i, j, l2;
	int l1 = 0;
	while (l1 + k <= n - 1) {
		l2 = l1 + k;
		u1 = l2 - 1;
		u2 = (l2 + k - 1 <= n - 1) ? 12 + k - 1 : n - 1;
		for (i = l1, j = l2; i <= u1 && j <= u2; m++) {
			if (a[i].key <= a[j].key) {
				swap[m] = a[i];
				i++;
			}
			else {
				swap[m] = a[j];
				j++;
			}
		}
		while (i <= u1) {
			swap[m] = a[i];
			m++;
			i++;
		}
		while (j <= u2) {
			swap[m] = a[j];
			m++;
			j++;
		}
		l1 = u2 + 1;
	}
	for (i = l1; i < n; i++, m++)
		swap[m] = a[i];
}
void MergeSort(datatype a[], int n) {
	int i, k = 1;
	datatype swap[100];
	while (k < n) {
		Merg(a, n, swap, k);
		for (i = 0; i < n; i++)
			a[i] = swap[i];
		k = 2 * k;
	}
	free(swap);
}

void suijiMergeSort() {        //归并排序结果
	datatype array[15];
	int i;
	printf("排序前生成随机数为：\n");
	srand((unsigned)time(NULL));
	for (i = 0; i < 15; i++) {
		array[i].key = rand() % 100;
		printf("%d  ", array[i].key);
	}
	printf("\n\n归并排序结果 ：\n");
	MergeSort(array, 15);
	for (i = 0; i < 15; i++) {
		printf("%d  ", array[i].key);
	}
	printf("\n");
}