[SOLVED] Homework 3 csci 1112

Social media describes a wide variety of applications where users provide ratings on ideas or services. Some examples
include Facebook, Reddit, Yelp, and Uber. A developer often leverages user rating data in order to promote information to other users. Some sites use a positive and negative rating approach where users can express their support or
dislike for particular information. The difference between positive and negative ratings is often referred to a ratio.One major consideration for a social media site is the volume of traffic and the frequency with which ratings may
change due to the evolving feedback from a large user base. Users are often attracted to social media sites to gather
real-time information such as using a social media site as a news proxy and demand often increases when a socially
significant event occurs, e.g. natural disaster, political process, or celebrity event.When designing a social media platform that organizes data by ratio, a developer must consider how to rapidly respond
to changing ratios. If ratio is the basis for organization of posts and if high volume can result in rapidly changing ratios,
then the developer will need to implement a policy that dictates the frequency of post sorting. Recall that sorting is
more expensive than searching and users demand fast responses, so it may be better to periodically index, i.e. sort, and
provide users with a “snapshot” of the index table in order to minimize the amount of sorting time.
When dealing with sorting, there are two important considerations that must be balanced: how fast must the sort be
and therefore how frequently the sort is performed, and how much memory is necessary to perform the sort. Which
of these considerations is the most important requirement is a matter of analyzing the requirements of the product that
you are developing. For a social media site on large servers where there is high frequency usage, speed trumps memory in requirements, but for other applications such as embedded code into a microcontroller where the data update is
infrequent, memory may be a much more significant concern.A framework for this program has been provided in SocialNet.java and a set of unit tests have been provided in
SoNetUnitTest.java. There is also a data file posts and a file reader PostReader.java that you should
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not modify but you are welcome to look at. In order to compile and test your work, compile SoNetUnitTest.java
and run SoNetUnitTest.The framework assumes a number of array based data structures which are consistently named or prefixed as posts,
view, post, and profile. This section specifies the intent and usage of the data structures.posts is a master list of post information. This data structure represents a snapshot from a large data set of post data
which may originate from a data base of some sort. As a snapshot, it reflects the current state of the post information
for the website at one instant in time. Consider that this information may be changing tens of thousands per second
and you might grasp the scale of the problem involved with designing an effective social media site.
The structure of posts consists of rows (1st dimension) of post records (2nd dimension). Each post record consists
of three fields of integers (see post below).A view is a referential (shallow) copy of the master list of posts. A view is a shallow copy because it will allow
changes to records in the master set of posts to be reflected in the view.
The structure of a view is the same as posts.A post is a record (or row) in a set of post data.
The structure of a post consists of an array of three integer values. The 1st field (index 0) is the post id which is an
identifier unique to each post. The 2nd field (index 1) is the number of “ups” or the number of positive responses to a
post. The 3rd field (index 2) is the number of “downs” or the number of negative responses to a post.A profile is an array that is used to track the performance of a sort.
The structure of a post consists of an array of three integer values. The 1st field (index 0) accumulates the number
of allocations on the stack that have been made during the sort. The 2nd field (index 1) accumulates the number of
comparisons that are made during a sort. The 3rd field (index 2) accumulates the number of swaps that are made
during a sort.It will be difficult to get a fully accurate measure for profile data and we really only want to get an idea of what the
hidden costs are. You will not count any of the profile operations or allocations, but you will count these actions
for the sort itself. When the profile data is printed for a full implementation, you should see orders of magnitude more
allocs for recursive over iterative and orders of magnitude more compares and swaps for iterative over recursive which
should help illustrate the hidden cost of these implementations
When profiling programs, we use a different approach; however, there is an important lesson about pass-by-value and
changing data accessed by reference type hidden in this approach especially when implementing the recursive sorting.The requirements in this section constitute a 90% solution. You must implement the following functions using the
following function signatures:
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public static int[][] createView(int[][] posts)
public static int differential(int[] post)
public static boolean lessThan(int[] post1, int[] post2)
public static void swapPosts(int[][] view, int i, int j)
public static int[] iterativeSort(int[][] view)This section gives a general explanation of the requirements for each function. More information may be available in
the function headers and in how the functions are unit tested.
int[][] createView(int[][] posts)
createView performs a shallow copy or referential copy of a set of posts into what is called a view and returns
the view. The intent is that if post information in the master set of posts changes, we want the information to be
known to the view. If we performed a deep copy, we would have to have a separate process to either recopy view or
to execute a large number of searches to update an existing view. Note the contrast between this requirement and the
requirements for Steganography.int differential(int[] post)
differential computes the virtual differential for a single post record and returns the differential.
The differential is simply the difference between ups and downs. differential is virtual because it is
not stored in a post record.
boolean lessThan(int[] post1, int[] post2)
lessThan performs a less than comparison between two post records where post1 acts as the left operand and
post2 acts as the right operand. The basis of comparison is the differential between the two operands. You
must use the differential method in this implementation.void swapPosts(int[][] view, int i, int j)
swapPosts performs a shallow swap between two post records (at indices i and j) in a view. This is a referential
swap and not a deep data swap. The intent is that the original post data in the master set of posts should be completely
unaffected by this swapping operation.int[] iterativeSort(int[][] view)
iterativeSort performs a sorting operation on a view (a referential view of the master set of posts) using
one of the iterative sorts that we discussed: selection, bubble, or insertion sort. iterativeSort returns an array
of profile information as detailed in the Data Structures section above. You may implement addition functions
to support this sorting operation; however, take care that the profile information is accurately maintained and
accounted for over any subsequent funtion calls.2.3 ExtensionThe requirements in this section represents the remaining 10% of your potential grade. You will receive no credit
for the extension if your base implementation is incorrect. Focus first on getting the base program fully correct,
then consider the extension requirements. You must implement the following functions using the following function
signatures:
public static int[] recursiveSort(int[][] view)int[] recursiveSort(int[][] view)
recursiveSort performs a sorting operation on a view (a referential view of the master set of posts) using
recursive quicksort. recursiveSort returns an array of profile information as detailed in the Data Structures
section above. You may implement addition functions to support this sorting operation; however, take care that the
profile information is accurately maintained and accounted for over any subsequent function calls.
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