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practiceItgrader.java
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practiceItgrader.java
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import java.util.*;
import java.io.*;
import java.security.MessageDigest;
import java.time.*;
public class PracticeItGrader {
// Set to true to output diagnostic debugging info
static boolean ifDebug = false;
// Set to true to change real student names (George) into hashed letters (AFLTZ)
static boolean ifEncrypt = false;
// Set to year,mo,day,h,m,s to calculate # of problems before that time
static LocalDateTime dtDeadline = LocalDateTime.of(2020,05,20,23,59,59); // LocalDateTime.of(2019,1,20,23,59,59);
public static void main(String[] args) throws FileNotFoundException {
// Problem class - type, number, time
ArrayList<Problem> problemList = null;
// Student class - name, array of problems
ArrayList<Student> studentList;
// true if a list of student names text file exists to filter the results
boolean ifClassList;
studentList = Student.readStudents();
ifClassList = studentList == null ? false : true;
// Reads list of assigned problems to filter results by
problemList = Problem.readAssignedProblems();
// Reads problems performed by students and stores into studentList, will create list if null
// problemList passed in for red flag detection
studentList = Problem.readProblems(studentList, problemList);
printResults(ifClassList, problemList, studentList);
}
public static void printResults(Boolean ifClassList, ArrayList<Problem> problemList, ArrayList<Student> studentList) {
// Output class list
int iStudent = 1;
if (ifDebug) {
System.out.println();
System.out.println("printResults Begin");
}
for (Student s : studentList) {
// Always print out the student usernames, if no class list this is all we'll do
System.out.printf("%s %s %s #%d ",
// Print encrypted names to hide student info when sharing samples
ifEncrypt ? Student.toHash(s.getUserName()) : s.getUserName(),
ifEncrypt ? Student.toHash(s.getFirstName()) : s.getFirstName(),
ifEncrypt ? Student.toHash(s.getLastName()) : s.getLastName(),
iStudent++);
// Only print problems if we already have the class list
if (ifClassList) {
ArrayList<Problem> assigned = (ArrayList<Problem>) problemList.clone();
ArrayList<Problem> extras = new ArrayList<Problem>();
ArrayList<Problem> failed = new ArrayList<Problem>();
int countAttemptByDeadline = 0, countOld = 0;
// This is an arbitrary # of days to flag "old" problems done for a previous class, etc
LocalDateTime dtStart = dtDeadline.minusDays(10);
// This is a list of all problem submission times
LinkedList<LocalDateTime> dates = new LinkedList<>();
for (int iProblem = 0; iProblem<s.getProblems().size(); iProblem++) {
Problem p = s.getProblems().get(iProblem);
int indexAssignedProblem = problemList.indexOf(p);
if (indexAssignedProblem != -1) {
Problem assignedProblem = problemList.get(indexAssignedProblem);
String studentName = s.getUserName();
if (p.getCodeHash().size() > 1)
System.out.printf("ERROR - student %s problem %s should only have one code hash\n", studentName, p);
assignedProblem.getCodeHash().put(studentName, p.getCodeHash().get(studentName));
assignedProblem.getTries().put(studentName, p.getTries().get(studentName));
}
int iRemove = -1;
if (assigned != null && (iRemove = assigned.indexOf(p)) != -1) {
// Problem is on the assigned list
// check if it's done by deadline
if (dtDeadline != null) {
if (p.getDate().compareTo(dtDeadline) <= 0)
countAttemptByDeadline++;
if (p.getDate().isBefore(dtStart))
countOld++;
dates.add(p.getDate());
}
if (!p.isIfCompleted())
failed.add(p);
// remove it from list of assigned problems
assigned.remove(iRemove);
} else {
// add it to the extras list
extras.add(p);
}
}
// Continue Print # attemped out of assigned, but don't count any extras
System.out.printf("Attempted %d of %d assigned\n",
s.getProblems().size() - extras.size(), problemList.size());
Collections.sort(assigned);
Collections.sort(failed);
Collections.sort(extras);
// Print "Missing SC 1.2", "Failed: SC 2.3", "Extras: Ex 3.4"
System.out.printf("\tMissing %d:", assigned.size());
for (Problem p: assigned)
System.out.printf(p.toString());
System.out.println();
System.out.printf("\tFailed %d: ", failed.size());
for (Problem p: failed)
System.out.printf(p.toString());
System.out.println();
System.out.printf("\tExtras %d: ", extras.size());
for (Problem p: extras)
System.out.printf(p.toString());
System.out.println();
// Print how many completed by deadline
if (dtDeadline != null) {
System.out.println("\t" + countAttemptByDeadline +
" assigned attempted before " +
dtDeadline.toString().substring(0,10));
System.out.println("\t" + countOld +
" done before " + dtStart.toString().substring(0,10));
}
Collections.sort(dates);
LocalDateTime dtCurrent = null;
if (!dates.isEmpty())
dtCurrent = dates.getFirst();
for (LocalDateTime dtNext : dates) {
// Find problem based on dtNext and store student's times
for (Problem p : s.getProblems()) {
if (p.getDate().equals(dtNext)) {
// Store this <Student, time> into the original problem list's map
int index = problemList.indexOf(p);
problemList.get(index).getTimes().put(s.userName, Duration.between(dtCurrent, dtNext).getSeconds());
}
}
dtCurrent = dtNext;
} // end examining all timestamps
} // end printing problems for a student in class
System.out.println(); // newline for each student
} // done with all students
System.out.println("******** BY PROBLEM ANALYSIS **********");
for (Problem p : problemList) {
// Only check the exercises
if (p.getType().equals("Self-Check"))
continue;
// debug breakpoint for a specific problem
// if (Problem.fInProblem(p, 9, 2))
// System.out.println("Breakpoint");
String result = "";
boolean fPrintedTimes = false;
// We have a map of all <Student Name, duration in min>
// Sort map into ArrayList based on durations
List<Map.Entry<String, Long>> studentTimeEntries = new ArrayList<> (p.getTimes().entrySet());
studentTimeEntries.sort(Map.Entry.comparingByValue());
// Eliminate bottom 0's which are student's first problems
while (studentTimeEntries.size() != 0 && studentTimeEntries.get(0).getValue() == 0)
studentTimeEntries.remove(0);
// Eliminate top times
// > 60 min which are likely after a break
// > 3x median outliers
int last = studentTimeEntries.size();
while (last != 0) {
long median = studentTimeEntries.get(studentTimeEntries.size()/2).getValue();
long maxTime = Math.max(median, 60*60);
if (studentTimeEntries.get(last-1).getValue() > maxTime) {
studentTimeEntries.remove(last-1);
last--;
} else
break;
}
if (studentTimeEntries.size() != 0) {
// Print out the whole range of times to see
result += String.format("(min)Times for %s are: ", p);
for (Map.Entry<String, Long>studentEntry : studentTimeEntries)
result += String.format(studentEntry.getValue()/60 + " ");
result += String.format("\n");
// Examine bottom third and flag times < half of median
int size = studentTimeEntries.size();
long medianTime = studentTimeEntries.get(size/2).getValue();
if (medianTime > 5*60) {// don't look at easy problems
int topTimeIndex = size/3;
result += String.format("(min)Times: median %d vs: ", medianTime/60);
for (int index = 0; index < topTimeIndex; index++) {
if (studentTimeEntries.get(index).getValue() < medianTime / 2) {
Map.Entry<String, Long> cheaterEntry = studentTimeEntries.get(index);
result += String.format("%s=%d ", cheaterEntry.getKey(), cheaterEntry.getValue()/60, medianTime/60);
flagCheater(studentList, cheaterEntry.getKey(), p, "Times");
fPrintedTimes = true;
}
}
result += String.format("\n"); // end Times line
}
} // reduced student times exist
if (fPrintedTimes)
System.out.print(result);
boolean fPrintedTries = false;
result = null;
List<Map.Entry<String, Integer>> triesEntries = new ArrayList<> (p.getTries().entrySet());
triesEntries.sort(Map.Entry.comparingByValue());
if (triesEntries.size() != 0) {
result += String.format("# Tries for %s are: ", p);
for (Map.Entry<String, Integer>studentEntry : triesEntries)
result += String.format(studentEntry.getValue() + " ");
result += String.format("\n");
int medianTries = triesEntries.get(triesEntries.size()/2).getValue();
if (triesEntries.get(0).getValue() < medianTries / 2) {
result += String.format("# Tries median %d vs: ", medianTries);
for (int index = 0; index < triesEntries.size(); index++) {
if (triesEntries.get(index).getValue() < medianTries / 2) {
Map.Entry<String, Integer> cheaterEntry = triesEntries.get(index);
result += String.format("%s=%d ", cheaterEntry.getKey(), cheaterEntry.getValue());
flagCheater(studentList, cheaterEntry.getKey(), p, "Tries");
fPrintedTries = true;
}
}
result += String.format("\n"); // new line after tries
} // cheaters to print
} // tries
if (fPrintedTries)
System.out.print(result);
Map<String, Integer> hashesMap = p.getCodeHash();
// only look for duplicates if 3/4th are unique
// only exercises worth checking
// put into set to determine uniqueness
// debughash - use this to find why duplicate code checking not catching
if (Problem.ifDebugHash && Problem.fInProblem(p, Problem.chapterDebugHash, Problem.problemDebugHash))
System.out.println("breakpoint");
Set<Integer> uniqueHashes = new HashSet<Integer>(hashesMap.values());
// filtering out problems with common dups prevented seeing true level of cheating
// instead you should rely upon large datasets identifying the real cheats
if (p.getType().equals("Exercise")) {
Map<Integer, ArrayList<String>> mapHashToNames = findCommonFlags(hashesMap);
// loop through each hash
for (int hash : mapHashToNames.keySet()) {
// print list of names
if (hash == 0) // ignore code that is too small
continue;
System.out.printf("Problem %s: duplicated by: %s\n", p, mapHashToNames.get(hash));
// if ** known cheater is in group, change to a red flag
String reason = "Code";
for (String name : mapHashToNames.get(hash)) {
if (name.startsWith("**"))
reason = "Red Flag";
}
for (String name : mapHashToNames.get(hash)) {
flagCheater(studentList, name, p, reason);
if (name.startsWith("**") == false)
System.out.printf("\t%s tried %d times in %d min\n", name, p.getTries().get(name), p.getTimes().get(name)/60);
}
}
} // looking for duplicate code hash
if ((fPrintedTimes || fPrintedTries) && p.getTimes().size() != 0)
System.out.println(); // separating line per problem if we've printed
}
// Sort by cheater scores
// This uses a anonymous class instead of creating a separate comparator class
Collections.sort(studentList, new Comparator<Student>() {
@Override
public int compare(Student s1, Student s2) {
return s2.getCheatingIndex() - s1.getCheatingIndex();
}
});
// Only print top 1/3rd of non-zero items
if (studentList.size() != 0) {
int end = studentList.size()-1;
while (end >= 0 && studentList.get(end).getCheatingIndex() == 0)
end--;
System.out.println("******** FINAL CHEATING ANALYSIS **********");
System.out.printf("Median cheating index was %d, Top 1/3rd suspicious are:\n",
studentList.get(end/2).getCheatingIndex());
int indexStudent = 0;
for (; indexStudent < studentList.size() / 3; indexStudent++)
printStudentCheatingReport(studentList.get(indexStudent));
System.out.printf("******** Other students with red flags ********\n");
Flag fake = new Flag(null, "red flag");
for (;indexStudent < studentList.size(); indexStudent++) {
if (studentList.get(indexStudent).getFlags().contains(fake)) {
for (Flag f : studentList.get(indexStudent).getFlags()) {
if (f.getReason().equals("red flag")) {
System.out.printf("Student %s red flag %s\n",
studentList.get(indexStudent).getUserName(),
f.getProblem());
}
}
}
}
} // studentList exists
if (ifDebug) {
System.out.println("printResults End");
}
} // end PrintResults
public static void flagCheater(ArrayList<Student> studentList, String cheaterName, Problem p, String reason) {
int seriousness = 0;
// Increase student's cheating index
int index = studentList.indexOf(new Student(cheaterName, null, null));
if (reason.equalsIgnoreCase("Tries")) {
seriousness = 1;
} else if (reason.equalsIgnoreCase("Times")) {
seriousness = 3;
} else if (reason.equalsIgnoreCase("Code")) {
seriousness = 5;
} else if (reason.equalsIgnoreCase("red flag")) {
seriousness = 10;
} else
System.out.printf("ERROR: unknown cheating flag\n", reason);
if (index != -1) {
Student s = studentList.get(index);
s.setCheatingIndex(s.getCheatingIndex()+seriousness);
Flag f = new Flag(p, reason);
// Red flags may go off multiple times in a problem - only flag it once
if (!reason.equals("red flag") || !s.getFlags().contains(f))
s.getFlags().add(f);
}
}
public static <T extends Comparable<T>> Map<T, ArrayList<String>> findCommonFlags(Map<String, T> input) {
List<Map.Entry<String, T>> listNameToFlag = new ArrayList<> (input.entrySet());
listNameToFlag.sort(Map.Entry.comparingByValue());
Map<T, ArrayList<String>> mapFlagToNames = new HashMap<>();
// loop through each hash backwards so we can remove easily
for (int index = listNameToFlag.size()-1; index > 0; index--) {
T item = listNameToFlag.get(index).getValue();
// if not unique
if (item.equals(listNameToFlag.get(index-1).getValue())) {
// create Map entry for the values from the original map
ArrayList<String> names = new ArrayList<String>();
mapFlagToNames.put(listNameToFlag.get(index).getValue(), names);
// add first name to list
names.add(listNameToFlag.get(index).getKey());
// remove any duplicates earlier in the list
while (index > 0 && item.equals(listNameToFlag.get(index-1).getValue())) {
names.add(listNameToFlag.get(index-1).getKey());
listNameToFlag.remove(index-1);
index--;
}
// remove first offender
listNameToFlag.remove(index);
} // not unique
} // loop through hashes
return mapFlagToNames;
}
public static void printStudentCheatingReport(Student s) {
if (s.cheatingIndex == 0)
return;
System.out.printf("**%s index %d\n", s.getUserName(), s.getCheatingIndex());
// Build Map of <reason, list<problem numbers> from list<flags>
Map<String, ArrayList<String>> mapFlagProb = new HashMap<String, ArrayList<String>>();
for (Flag flag : s.getFlags()) {
// build arrayList if first of flag type
if (!mapFlagProb.containsKey(flag.getReason()))
mapFlagProb.put(flag.getReason(), new ArrayList<String>());
mapFlagProb.get(flag.getReason()).add(flag.getProblem().toString());
}
// Print out each flag type : list of problems
for (String reason : mapFlagProb.keySet()) {
System.out.print(reason + ": ");
for (String problemNum : mapFlagProb.get(reason))
System.out.printf(problemNum);
System.out.println(); // new line for each reason
}
}
}