# 程序代写代做代考 Java scheme algorithm COMP9313 2017s1 Project 2

COMP9313 2017s1 Project 2

Problem statement – single target shortest path:

Given a graph and a node “t”, find the shortest distances of all nodes to “t”.

For example, the shortest distance from node 1 to t is 7 with path 1->3->4->t.

Please note that this is different from the single-source shortest path

problem!! However, you can make minor modifications to the algorithm for

that problem to solve this one.

Input files:

In the input file, each line is in format of:

“EdgeId FromNodeId ToNodeId Distance”.

In the above example, the input contains (assume t is given node id 0):

0 0 1 10.0

1 1 2 3.0

2 1 3 1.0

3 2 1 3.0

4 2 0 5.0

5 2 3 9.0

6 2 4 2.0

7 3 4 4.0

8 4 0 2.0

9 4 3 6.0

https://webcms3.cse.unsw.edu.au/COMP9313/17s1/resources/7305

Output:

Set the number of reducers to 1. The single output file contains the shortest

distances of all nodes to the given node. Each line is in format of

“QueryNodeID SourceNodeID Distance”. The shortest distances are of

double precision. Remove the nodes that are not reachable to the query node,

and sort the output by SourceNodeID according to its numeric value. Given

the example graph, the output file is like:

0 0 0.0

0 1 7.0

0 2 4.0

0 3 6.0

0 4 2.0

Code format:

Name your java file as “SingleTargetSP.java”, and put it in the package

“comp9313.ass2”. Your program should take three parameters: the input

graph file, the output folder (which stores the final result file), and the query

target node id.

One difficulty of this problem is how to do the iterative MapReduce jobs.

https://webcms3.cse.unsw.edu.au/COMP9313/17s1/resources/7306, which

may help you to solve this problem. Another difficulty is how to check the

termination criterion, and you are required to utilize the counter to do this

job.

Notes:

1. After the iterations are finished (i.e., all shortest distances are found),

the output format is not as required. Thus, you need to use another

round map/reduce to convert the output to the desired format. Please

use the output folder given in the parameter to store the final result.

2. Before coding, please write down the pseudocode for this problem

(using word or latex), and submit your pseudocode in the pdf format.

https://webcms3.cse.unsw.edu.au/COMP9313/17s1/resources/7305
https://webcms3.cse.unsw.edu.au/COMP9313/17s1/resources/7306

Your source code will be inspected and marked based on readability and

ease of understanding. The documentation (comments of the codes) in your

source code is also important. Below is an indicative marking scheme:

Result correctness: 80%

Pseudocode: 10%

Documentation: 10%

Submission:

Deadline: Sunday 23th April 09:59:59 PM

Log in any CSE server (williams or wagner), and use the give command

\$ give cs9313 assignment2 Pseudocode.pdf SingleTargetSP.java

Or you can submit through:

https://cgi.cse.unsw.edu.au/~give/Student/give.php

If you submit your assignment more than once, the last submission will

replace the previous one. To prove successful submission, please take a

screenshot as assignment submission instructions show and keep it by

yourself.

Late submission penalty

10% reduction of your marks for the 1st day, 30% reduction/day for the

following days.

Plagiarism:

The work you submit must be your own work. Submission of work partially

or completely derived from any other person or jointly written with any

other person is not permitted. The penalties for such an offence may include

negative marks, automatic failure of the course and possibly other academic

discipline. Assignment submissions will be examined manually.

Relevant scholarship authorities will be informed if students holding

https://cgi.cse.unsw.edu.au/~give/Student/give.php

scholarships are involved in an incident of plagiarism or other misconduct.

Do not provide or show your assignment work to any other person – apart

from the teaching staff of this subject. If you knowingly provide or show

your assignment work to another person for any reason, and work derived

from it is submitted you may be penalized, even if the work was submitted