学步园

1.快速排序

/* By LYLtim */

void swap (int *a, int *b)
{
	int t = *a; *a = *b; *b = t;
}

void QSort(int a[], int l, int r)
{
	int pl = l, pr = r, key = a[(l+r)>>1];
	while (pl < pr) {
		while (a[pl] < key) pl++;
		while (a[pr] > key) pr--;
		if (pl <= pr) {
			swap(&a[pl], &a[pr]);
			pl++; pr--;
		}
	}
	if (pl < r) QSort(a, pl, r);
	if (pr > l) QSort(a, l, pr);
}

2.归并排序

/* By LYLtim */

void merge(int start, int mid, int end)
{
	int	pl, pr, p = start,
		len1 = mid - start + 1,
		len2 = end - mid,
		left[len1], right[len2];
	for (pl = 0; pl < len1; pl++) left[pl] = a[start+pl];
	for (pr = 0; pr < len2; pr++) right[pr] = a[mid+1+pr];
	pl = pr = 0;
	while (pl < len1 && pr < len2)
		if (left[pl] < right[pr]) a[p++] = left[pl++];
		else a[p++] = right[pr++];
	while (pl < len1) a[p++] = left[pl++];
	while (pr < len2) a[p++] = right[pr++];
}
			
void sort(int start, int end)
{
	if (start < end) {
		int mid = (start + end) >> 1;
		sort(start, mid);
		sort(mid+1, end);
		merge(start, mid, end);
	}
}