/**
* Returns an List of ScheduleStates with the schedules from the currentstate updated with the
* new schedules with course in place.
*/
private List <ScheduleState> insertIntoSchedule(ScheduleState currentState, Course course,
int period, List <string> possibleSchedules)
{
List <ScheduleState> results = new List <ScheduleState>();
//Get the domainOfCourses and pop the first one off the stack.
Stack <Course> domainOfCourses = currentState.getCourses();
Course currentCourse = domainOfCourses.Pop();
//Loop through the possible schedules.
foreach (string possSchedule in possibleSchedules)
{
//Create a new ScheduleState with the current schedules and the remaining domainOfCourses.
ScheduleState state = new ScheduleState(currentState.getSchedules(), domainOfCourses);
Schedule classSchedule = state.getSchedule(currentCourse.getCourseRoom());
Schedule teacherSchedule = state.getSchedule(currentCourse.getTeacherName());
//Update the schedule.
for (int i = 0; i < possSchedule.Length; i++)
{
switch (possSchedule[i])
{
case 'M':
classSchedule.setCourse(0, period, currentCourse);
teacherSchedule.setCourse(0, period, currentCourse);
break;
case 'T':
classSchedule.setCourse(1, period, currentCourse);
teacherSchedule.setCourse(1, period, currentCourse);
break;
case 'W':
classSchedule.setCourse(2, period, currentCourse);
teacherSchedule.setCourse(2, period, currentCourse);
break;
case 'R':
classSchedule.setCourse(3, period, currentCourse);
teacherSchedule.setCourse(3, period, currentCourse);
break;
case 'F':
classSchedule.setCourse(4, period, currentCourse);
teacherSchedule.setCourse(4, period, currentCourse);
break;
}
}
results.Add(state);
}
return(results);
}
/**
* Recursive backtracking search method using the remaining problem. This method contains the algorithm
* for the backtracking search.
*/
private ScheduleState recursiveBacktrackingSearch(CSPSearchAgent remainingProblem)
{
//Check if the problem is complete.
if (remainingProblem.isComplete())
{
//If so, return the completed scheduleState
return(remainingProblem.getScheduleState());
}
//Retrieve an array of successorStates from the CSPSearchAgent.
List <ScheduleState> successorStates = remainingProblem.getSuccessors();
//Loop through the successor states.
foreach (ScheduleState state in successorStates)
{
//Create a new CSPSearchAgent using the new successor state
CSPSearchAgent nextProblem = new CSPSearchAgent(state);
//If the problem does not violate constraints
if (nextProblem.checkConstraints() == true)
{
//Recursively search the next set.
ScheduleState result = recursiveBacktrackingSearch(nextProblem);
//If the result from the recursion is null,
if (result == null)
{
//continue with the next state in the for loop.
continue;
}
//Otherwise,
else
{
//return the result.
return(result);
}
}
}
//If no solution is found, return null.
return(null);
}
/**
* Takes the course and finds all successor states for that course. Returns an ArrayList containing the
* successors.
*/
private List <ScheduleState> getArrayListOfSuccessors(ScheduleState currentState, Course course)
{
//ArrayList of ScheduleStates to house results.
List <ScheduleState> results = new List <ScheduleState>();
//Get the class and teacher's schedules for the given course.
Schedule classSchedule = currentState.getSchedule(course.getCourseRoom());
Schedule teacherSchedule = currentState.getSchedule(course.getTeacherName());
//For each period in the day
for (int period = 0; period < classSchedule.getNumberOfPeriods(); period++)
{
//Get the list of possible days between the teacher and class schedules
string daysPossible = intersectionOfStrings(classSchedule.openSlotsInSchedule(course, period),
teacherSchedule.openSlotsInSchedule(course, period));
//Get the possible schedules for the class.
List <string> possibleSchedules = getPossibleSchedules(daysPossible, course.getDaysPerWeek());
results.AddRange(insertIntoSchedule(currentState, course, period, possibleSchedules));
}
return(results);
}
/**
* Constructor taking the ScheduleState and creating a search agent for it.
*/
public CSPSearchAgent(ScheduleState scheduleState)
{
//Assign it as the local variable.
this.currentState = scheduleState;
}
/**
* Returns an List of ScheduleStates with the schedules from the currentstate updated with the
* new schedules with course in place.
*/
private List<ScheduleState> insertIntoSchedule(ScheduleState currentState, Course course,
int period, List<string> possibleSchedules)
{
List<ScheduleState> results = new List<ScheduleState>();
//Get the domainOfCourses and pop the first one off the stack.
Stack<Course> domainOfCourses = currentState.getCourses();
Course currentCourse = domainOfCourses.Pop();
//Loop through the possible schedules.
foreach (string possSchedule in possibleSchedules)
{
//Create a new ScheduleState with the current schedules and the remaining domainOfCourses.
ScheduleState state = new ScheduleState(currentState.getSchedules(), domainOfCourses);
Schedule classSchedule = state.getSchedule(currentCourse.getCourseRoom());
Schedule teacherSchedule = state.getSchedule(currentCourse.getTeacherName());
//Update the schedule.
for (int i = 0; i < possSchedule.Length; i++)
{
switch (possSchedule[i])
{
case 'M':
classSchedule.setCourse(0, period, currentCourse);
teacherSchedule.setCourse(0, period, currentCourse);
break;
case 'T':
classSchedule.setCourse(1, period, currentCourse);
teacherSchedule.setCourse(1, period, currentCourse);
break;
case 'W':
classSchedule.setCourse(2, period, currentCourse);
teacherSchedule.setCourse(2, period, currentCourse);
break;
case 'R':
classSchedule.setCourse(3, period, currentCourse);
teacherSchedule.setCourse(3, period, currentCourse);
break;
case 'F':
classSchedule.setCourse(4, period, currentCourse);
teacherSchedule.setCourse(4, period, currentCourse);
break;
}
}
results.Add(state);
}
return results;
}
/**
* Takes the course and finds all successor states for that course. Returns an ArrayList containing the
* successors.
*/
private List<ScheduleState> getArrayListOfSuccessors(ScheduleState currentState, Course course)
{
//ArrayList of ScheduleStates to house results.
List<ScheduleState> results = new List<ScheduleState>();
//Get the class and teacher's schedules for the given course.
Schedule classSchedule = currentState.getSchedule(course.getCourseRoom());
Schedule teacherSchedule = currentState.getSchedule(course.getTeacherName());
//For each period in the day
for (int period = 0; period < classSchedule.getNumberOfPeriods(); period++)
{
//Get the list of possible days between the teacher and class schedules
string daysPossible = intersectionOfStrings(classSchedule.openSlotsInSchedule(course, period),
teacherSchedule.openSlotsInSchedule(course, period));
//Get the possible schedules for the class.
List<string> possibleSchedules = getPossibleSchedules(daysPossible, course.getDaysPerWeek());
results.AddRange(insertIntoSchedule(currentState, course, period, possibleSchedules));
}
return results;
}
/**
* Constructor taking the ScheduleState and creating a search agent for it.
*/
public CSPSearchAgent(ScheduleState scheduleState)
{
//Assign it as the local variable.
this.currentState = scheduleState;
}