Method swap

src/class027/Code02_MaxCover.java:97–101

(int i, int j)

	}

	public static void swap(int i, int j) {
		int tmp = heap[i];
		heap[i] = heap[j];
		heap[j] = tmp;
	}

	// 也找到了leetcode测试链接
	// 测试链接 : https://leetcode.cn/problems/meeting-rooms-ii/