private static List<Schedule> generateSchedules(
List<ArrayList<CourseSelection>> selections, int count) {
List<Schedule> schedules = new ArrayList<Schedule>();
if (count == 0) {
for (CourseSelection cs : selections.get(count)) {
// This is one course's course selections.
schedules.add(new Schedule(cs));
}
} else {
schedules = generateSchedules(selections, count - 1);
List<Schedule> nextSchedules = new ArrayList<Schedule>();
for (Schedule s : schedules) {
for (CourseSelection cs : selections.get(count)) {
if (!s.collidesWith(cs)) {
List<CourseSelection> temp = s.getCourseSelections();
Schedule result = new Schedule(cs);
for (int i = 0; i < temp.size(); i++) {
result.addCourseSelection(temp.get(i));
}
nextSchedules.add(result);
}
}
}
return nextSchedules;
}
return schedules;
}
public static List<Schedule> generateSchedules(
List<Course> selectedCourses, List<Course> optionalCourses, int requiredOptional) {
// Welcome to the worst sub of your life.
// Original schedules: generate your mandatory course schedules. Easy.
List<Schedule> originalSchedules = new ArrayList<Schedule>();
if (selectedCourses.size() > 0) {
originalSchedules = generateSchedules(selectedCourses);
}
// A string list to hold gray code.
List<String[]> nChooseK = new ArrayList<String[]>();
// Creates the digits that will be used, depending on how many optional courses there are.
String[] inputs = new String[optionalCourses.size()];
for (int j = 0; j < optionalCourses.size(); j++) {
inputs[j] = Integer.toString(j);
}
// Run the gray code nChooseK sub.
nChooseK = nChooseK(inputs, requiredOptional, 0, new String[requiredOptional], nChooseK);
// Final schedules will be returned to the user.
List<Schedule> finalSchedules = new ArrayList<Schedule>();
// For each string array in nChooseK, meaning for each possible gray code...
for (String[] sArray : nChooseK) {
// A temporary schedule holder.
List<Schedule> tempSchedules;
// A temporary selections holder
List<ArrayList<CourseSelection>> selections = new ArrayList<ArrayList<CourseSelection>>();
// Of the nChooseK string, we add k courses to selections.
for (String s : sArray) {
selections.add(
(ArrayList<CourseSelection>)
optionalCourses.get(Integer.parseInt(s)).getCourseSelections());
}
tempSchedules = generateSchedules(selections, requiredOptional - 1);
// Now we must merge tempSchedules with original schedules into final schedules.
if (originalSchedules.size() == 0) {
for (Schedule s : tempSchedules) {
finalSchedules.add(s);
}
} else {
for (Schedule s1 : originalSchedules) { // For every schedule generated previously,
for (Schedule s2 : tempSchedules) {
boolean valid = true;
for (CourseSelection cs : s2.getCourseSelections()) {
if (s1.collidesWith(cs)) {
valid = false;
}
}
if (valid) {
// We found a valid match. Let's add them to the final list.
List<CourseSelection> temp1 = s1.getCourseSelections();
List<CourseSelection> temp2 = s2.getCourseSelections();
Schedule result = null;
for (CourseSelection cs : temp1) {
if (result == null) {
result = new Schedule(cs);
} else {
result.addCourseSelection(cs);
}
}
for (CourseSelection cs : temp2) {
result.addCourseSelection(cs);
}
finalSchedules.add(result);
}
}
}
}
}
return finalSchedules;
}
