排序算法

快排

void mysort(int l, int r) {
	if (l == r) return;

	int mid = (l + r) / 2;
	mysort(l, mid);
	mysort(mid + 1, r);

	int i = l;
	int j = mid + 1;
	int k = l;
	while (i <= mid && j <= r) {
		if (a[i] <= a[j]) {
			b[k++] = a[i++];
		}
		else {
			b[k++] = a[j++];
		}
	}
	while (i <= mid) {
		b[k++] = a[i++];
	}
	while (j <= r) {
		b[k++] = a[j++];
	}
	for (int t = l; t <= r; t++) {
		a[t] = b[t];
	}
}

归并排序

void mysort2(int l, int r) {
	if (l >= r) return;
	int mid = (l + r) / 2;
	int i = l;
	int j = r;
	int flag = a[i];
	while (i<j) {
		while (i < j && flag <= a[j]) {
			j--;
		}
		a[i] = a[j];
		while (i < j && a[i] <= flag) {
			i++;
		}
		a[j] = a[i];
	}
	a[i] = flag;
	mysort2(l, i);
	mysort2(i + 1, r);
}