step 3 works first try

src/main.c

@@ -53,10 +53,10 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
   // uint8_t BLOCKS_PER_SEMESTER = TOTAL_BLOCKS / 2;
 
 
-  // Step 1 - Tally requests to check which courses are eligable to run
+  /*** STEP 1 - Tally requests to check which courses are eligable to run ***/
   char activeCourses[MAX_COURSES][MAX_COURSE_NO_LEN] = {{"\0"}};
   size_t activeCoursesIndexes[MAX_COURSES] = {0};
-  uint16_t activeCourseIndex = 0; // also acts as the length of activeCourses
+  uint16_t activeCoursesLen = 0; // also acts as the length of activeCourses
   for (size_t i = 0; i < size_students; i++) {
     for (size_t j = 0; j < students[i].requestsLen; j++) {
       if (students[i].requests[j].alternate) continue;
@@ -67,13 +67,13 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
         if (strcmp(courses[k].crsNo, students[i].requests[j].crsNo) == 0) {
           courses[k].requests++;
           if (courses[k].requests >= MIN_REQ) {
-            if (activeCourseIndex == 0) {
-              strcpy(activeCourses[activeCourseIndex], courses[k].crsNo);
-              activeCoursesIndexes[activeCourseIndex] = k;
-              activeCourseIndex++;
+            if (activeCoursesLen == 0) {
+              strcpy(activeCourses[activeCoursesLen], courses[k].crsNo);
+              activeCoursesIndexes[activeCoursesLen] = k;
+              activeCoursesLen++;
             } else {
               bool exists = false;
-              for (size_t l = 0; l < activeCourseIndex; l++) {
+              for (size_t l = 0; l < activeCoursesLen; l++) {
                 if (strcmp(activeCourses[l], courses[k].crsNo) == 0) {
                   exists = true;
                   break;
@@ -81,9 +81,9 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
               }
 
               if (!exists) {
-                strcpy(activeCourses[activeCourseIndex], courses[k].crsNo);
-                activeCoursesIndexes[activeCourseIndex] = k;
-                activeCourseIndex++;
+                strcpy(activeCourses[activeCoursesLen], courses[k].crsNo);
+                activeCoursesIndexes[activeCoursesLen] = k;
+                activeCoursesLen++;
               }
             }
           }
@@ -94,43 +94,44 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
   }
 
 
-  // Step 2 - Generate classes with no students, but calculate the number of expected students per class
+  /*** STEP 2 - Generate classes with no students, but calculate the number of expected students per class ***/
 
-  char hex[] = "0123456789abcdefABCDEF"; // Used to get a unique character to identify different classes of the same course
+  char hex[] = "0123456789abcdefABCDEF";
 
-  uint8_t *allClassRunCounts = malloc(activeCourseIndex * sizeof(uint8_t));
-  CLASS *emptyClasses = malloc(CLASSROOMS * TOTAL_BLOCKS * sizeof(CLASS)); // max this out to total number of classrooms available between both semesters
-  size_t currentIndex = 0;
-  for (size_t i = 0; i < activeCourseIndex; i++) {
+  uint8_t *allClassRunCounts = malloc(activeCoursesLen * sizeof(uint8_t));
+  // max this out to total number of classrooms available between both semesters
+  CLASS *classes = malloc(CLASSROOMS * TOTAL_BLOCKS * sizeof(CLASS));
+  size_t classesLen = 0;
+  for (size_t i = 0; i < activeCoursesLen; i++) {
     uint16_t index = activeCoursesIndexes[i];
     uint8_t classRunCount = floor((float) courses[index].requests / MEDIAN);
     uint8_t remaining = courses[index].requests % MEDIAN;
 
-    size_t *courseClassIndexes = malloc((classRunCount + 1) * sizeof(size_t)); // add 1 to classRunCount in case we need to create an extra class with remaining
+    // add 1 to classRunCount in case we need to create an extra class with remaining
+    size_t *courseClassIndexes = malloc((classRunCount + 1) * sizeof(size_t));
     for (size_t j = 0; j < classRunCount; j++) {
       CLASS newClass;
-      char courseID[MAX_COURSE_NO_LEN + 3]; // +3 = "_n\0" where n is the ID
+      strcpy(newClass.baseCrsNo, courses[index].crsNo);
+      char courseID[MAX_COURSE_ID_LEN];
       strcpy(courseID, courses[index].crsNo);
       appendChar(courseID, hex[j]);
       strcpy(newClass.crsNo, courseID);
       strcpy(newClass.description, courses[index].description);
       newClass.numberOfStudents = MEDIAN; // The expected number of students in this class
 
-      // CLASS_HASH emptyClass;
-      // strcpy(emptyClass.key, courses[index].crsNo);
-      // emptyClass.class = newClass;
-      // emptyClasses[currentIndex] = emptyClass;
-      emptyClasses[currentIndex] = newClass;
-      courseClassIndexes[j] = currentIndex;
-      currentIndex++;
+      classes[classesLen] = newClass;
+      courseClassIndexes[j] = classesLen;
+      classesLen++;
     }
 
-    // Handle remaining requests
+    //*** Handle remaining requests ***/
     
     // Can we add remaining requests to existing classes
     bool remainingFitsInExistingClasses = remaining <= classRunCount * (CLASS_CAP - MEDIAN);
+    
     // Can we create a new class using only remaining requests
     bool remainingCanCreateNewClass = remaining >= MIN_REQ;
+    
     // Can we create a new class if we borrow students from created classes to add to remaining requests to meet min req
     bool remainingPlusExtraFromExistingCanCreateNewClass = MIN_REQ - remaining < classRunCount * (MEDIAN - MIN_REQ);
     
@@ -138,7 +139,7 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
       // Simply add remaining to existing classes
       while (remaining > 0) {
         for (size_t j = 0; j < classRunCount; j++) {
-          emptyClasses[courseClassIndexes[j]].numberOfStudents++;
+          classes[courseClassIndexes[j]].numberOfStudents++;
           remaining--;
           if (remaining == 0) break;
         }
@@ -147,7 +148,8 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
     } else if (remainingCanCreateNewClass) {
       // Create new class
       CLASS newClass;
-      char courseID[MAX_COURSE_NO_LEN + 3]; // +3 = "_n\0" where n is the ID
+      strcpy(newClass.baseCrsNo, courses[index].crsNo);
+      char courseID[MAX_COURSE_ID_LEN];
       strcpy(courseID, courses[index].crsNo);
       appendChar(courseID, hex[classRunCount]);
       strcpy(newClass.crsNo, courseID);
@@ -155,20 +157,20 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
       newClass.numberOfStudents = remaining;
 
       // Insert class into empty classes array and update index
-      emptyClasses[currentIndex] = newClass;
-      courseClassIndexes[classRunCount] = currentIndex;
-      currentIndex++;
+      classes[classesLen] = newClass;
+      courseClassIndexes[classRunCount] = classesLen;
+      classesLen++;
 
       // update class run count; if there is more than one class, equalize the class number of students
       classRunCount++;
       if (classRunCount >= 2) {
         uint8_t *numberOfStudentsArr = malloc(classRunCount * sizeof(uint8_t));
         for (size_t j = 0; j < classRunCount; j++)
-          numberOfStudentsArr[j] = emptyClasses[courseClassIndexes[j]].numberOfStudents;
+          numberOfStudentsArr[j] = classes[courseClassIndexes[j]].numberOfStudents;
 
         numberOfStudentsArr = equal(numberOfStudentsArr, classRunCount);
         for (size_t j = 0; j < classRunCount; j++)
-          emptyClasses[courseClassIndexes[j]].numberOfStudents = numberOfStudentsArr[j];
+          classes[courseClassIndexes[j]].numberOfStudents = numberOfStudentsArr[j];
 
         free(numberOfStudentsArr);
       }
@@ -177,7 +179,7 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
       // Take 1 student from each existing class till min requirement is met
       while (remaining < MIN_REQ) {
         for (size_t j = 0; j < classRunCount; j++) {
-          emptyClasses[courseClassIndexes[j]].numberOfStudents--;
+          classes[courseClassIndexes[j]].numberOfStudents--;
           remaining++;
           if (remaining == MIN_REQ) break;
         }
@@ -185,7 +187,8 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
 
       // Create new class with remaining
       CLASS newClass;
-      char courseID[MAX_COURSE_NO_LEN + 3]; // +3 = "_n\0" where n is the ID
+      strcpy(newClass.baseCrsNo, courses[index].crsNo);
+      char courseID[MAX_COURSE_ID_LEN];
       strcpy(courseID, courses[index].crsNo);
       appendChar(courseID, hex[classRunCount]);
       strcpy(newClass.crsNo, courseID);
@@ -193,19 +196,19 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
       newClass.numberOfStudents = remaining;
 
       // Insert class into empty classes array and update index
-      emptyClasses[currentIndex] = newClass;
-      courseClassIndexes[classRunCount] = currentIndex;
-      currentIndex++;
+      classes[classesLen] = newClass;
+      courseClassIndexes[classRunCount] = classesLen;
+      classesLen++;
       classRunCount++;
 
       // Equalize the class number of students
       uint8_t *numberOfStudentsArr = malloc(classRunCount * sizeof(uint8_t));
       for (size_t j = 0; j < classRunCount; j++)
-        numberOfStudentsArr[j] = emptyClasses[courseClassIndexes[j]].numberOfStudents;
+        numberOfStudentsArr[j] = classes[courseClassIndexes[j]].numberOfStudents;
 
       numberOfStudentsArr = equal(numberOfStudentsArr, classRunCount);
       for (size_t j = 0; j < classRunCount; j++)
-        emptyClasses[courseClassIndexes[j]].numberOfStudents = numberOfStudentsArr[j];
+        classes[courseClassIndexes[j]].numberOfStudents = numberOfStudentsArr[j];
 
       free(numberOfStudentsArr);
 
@@ -220,13 +223,13 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
       bool full = false;
       while (!full) {
         for (size_t j = 0; j < classRunCount; j++) {
-          if (emptyClasses[courseClassIndexes[classRunCount - 1]].numberOfStudents == CLASS_CAP) {
+          if (classes[courseClassIndexes[classRunCount - 1]].numberOfStudents == CLASS_CAP) {
             // If the last class in the array is at class_cap, all other classes must be at class cap and we are full
             full = true;
             break;
           }
 
-          emptyClasses[courseClassIndexes[j]].numberOfStudents++;
+          classes[courseClassIndexes[j]].numberOfStudents++;
           remaining--;
         }
       }
@@ -236,9 +239,155 @@ TIMETABLE generateTimetable(STUDENT *students, size_t size_students, COURSE *cou
     allClassRunCounts[i] = classRunCount;
   }
 
+  // realloc classes to correct size
+  CLASS *tempclasses = malloc(classesLen * sizeof(CLASS));
+  for (size_t i = 0; i < classesLen; i++)
+    tempclasses[i] = classes[i];
+  classes = realloc(classes, classesLen * sizeof(CLASS));
+  memcpy(classes, tempclasses, classesLen * sizeof(CLASS));
+  free(tempclasses);
+
+
+  /*** STEP 3 - Insert students into empty classes ... yikes ***/
+  STUDENT *tempStudents = malloc(size_students * sizeof(STUDENT));
+  size_t size_tempStudents = size_students;
+  memcpy(tempStudents, students, size_students * sizeof(STUDENT));
+
+  uint8_t *currentInserted = malloc(classesLen * sizeof(uint8_t));
+  for (size_t i = 0; i < classesLen; i++)
+    currentInserted[i] = 0;
+
+  while (size_tempStudents > 0) {
+    // Choose student at random, to prevent success bias to students first in the array
+    STUDENT student = tempStudents[rand() % size_tempStudents];
+    // printf("pupilNum: %d\n", student.pupilNum);
+
+    // Create an array of students alternates
+    size_t numberOfAlts = 0;
+    for (size_t i = 0; i < student.requestsLen; i++)
+      if (student.requests[i].alternate)
+        numberOfAlts++;  
+ 
+    REQUEST *alternates = malloc(numberOfAlts * sizeof(REQUEST));
+    size_t alternateIdx = 0;
+    for (size_t i = 0; i < student.requestsLen; i++) {
+      if (student.requests[i].alternate) {
+        alternates[alternateIdx] = student.requests[i];
+        alternateIdx++;
+      }
+    }
+
+    // Search existing classes to insert student based off request
+    for (size_t i = 0; i < student.requestsLen; i++) {
+      if (student.requests[i].alternate) continue; // Ignore alternates
+      char course[MAX_COURSE_NO_LEN] = {"\0"};
+      strcpy(course, student.requests[i].crsNo);
+      bool getAvailableCourse = true;
+      bool isAlt = false;
+      // printf("getting available course for %s...\n", course);
+      while (getAvailableCourse) {
+        // printf("searching...\n");
+        for (size_t j = 0; j < classesLen; j++) {
+          // Class exists in classes
+          // printf("comparing target %s to %s at idx %ld\n", course, classes[j].crsNo, j);
+          if (strcmp(classes[j].baseCrsNo, course) == 0) {
+            // printf("course %s exists\n", course);
+            // If this is an alternate, and there is room to expand, increase number of students to allow extra
+            if (isAlt && classes[j].numberOfStudents < CLASS_CAP)
+              classes[j].numberOfStudents++;
+
+            // Class exists with room for student
+            if (currentInserted[j] < classes[j].numberOfStudents) {
+              classes[j].students[currentInserted[j]] = student.pupilNum;
+              currentInserted[j]++;
+              getAvailableCourse = false;
+              break;
+
+            } else if (currentInserted[j] == classes[j].numberOfStudents) {
+              // If class is full, and there's no more classes available for that course, convert to alt
+              if (j == classesLen - 1 || (j != classesLen - 1 && strcmp(classes[j + 1].baseCrsNo, course) != 0)) {
+                if (numberOfAlts > 0) {
+                  // Use alternate
+                  strcpy(course, alternates[0].crsNo); // asign alternate to course and retry
+                  // remove alternate from array of alts to retry same alt over and over
+                  REQUEST *tempAlternates = malloc(numberOfAlts * sizeof(REQUEST));
+                  memcpy(tempAlternates, alternates, numberOfAlts * sizeof(REQUEST));
+                  numberOfAlts--;
+                  alternates = realloc(alternates, numberOfAlts * sizeof(REQUEST));
+                  for (size_t k = 1; k <= numberOfAlts; k++)
+                    alternates[k - 1] = tempAlternates[k];
+                  free(tempAlternates);
+                  isAlt = true;
+                  break;
+                } else {
+                  // Force break the loop, ignore as it cannot be resolved
+                  // Allow administrator to handle error manually
+                  getAvailableCourse = false;
+                  break;
+                }
+              }
+            }
+            // this class does not exist, i.e not enough requests
+          } else if (j == classesLen - 1) {
+            // printf("course %s does not exist\n", course);
+            if (numberOfAlts > 0) {
+              // Use alternate
+              strcpy(course, alternates[0].crsNo); // asign alternate to course and retry
+              // remove alternate from array of alts to retry same alt over and over
+              REQUEST *tempAlternates = malloc(numberOfAlts * sizeof(REQUEST));
+              memcpy(tempAlternates, alternates, numberOfAlts * sizeof(REQUEST));
+              numberOfAlts--;
+              alternates = realloc(alternates, numberOfAlts * sizeof(REQUEST));
+              for (size_t k = 1; k <= numberOfAlts; k++)
+                alternates[k - 1] = tempAlternates[k];
+              free(tempAlternates);
+              isAlt = true;
+              break;
+            } else {
+              // Force break the loop, ignore as it cannot be resolved
+              // Allow administrator to handle error manually
+              getAvailableCourse = false;
+              break;
+            }
+          }
+        }
+      }
+      // printf("got available course for %s...\n", course); 
+    }
+
+    // Asign remaining alternates to student
+    for (size_t i = 0; i < size_students; i++) {
+      if (students[i].pupilNum == student.pupilNum) {
+        students[i].remainingAlts = realloc(students[i].remainingAlts, numberOfAlts * sizeof(REQUEST));
+        memcpy(students[i].remainingAlts, alternates, numberOfAlts * sizeof(REQUEST));
+        students[i].remainingAltsLen = numberOfAlts;
+        break;
+      }
+    }
+    free(alternates);
+
+    // realloc tempStudents to be size_tempStudents - 1 without struct of student just processed
+    size_tempStudents--;
+    STUDENT *new_tempStudents = malloc(size_tempStudents * sizeof(STUDENT));
+    size_t idx = 0;
+    for (size_t i = 0; i <= size_tempStudents; i++) {
+      if (tempStudents[i].pupilNum != student.pupilNum) {
+        new_tempStudents[idx] = tempStudents[i];
+        idx++;
+      }
+    }
+
+    tempStudents = realloc(tempStudents, size_tempStudents * sizeof(STUDENT));
+    memcpy(tempStudents, new_tempStudents, size_tempStudents * sizeof(STUDENT));
+    free(new_tempStudents);
+  }
+
+  free(currentInserted);
+  free(tempStudents);
+
   // DO MORE ALGORITHM
 
-  free(emptyClasses);
+  free(classes);
   free(allClassRunCounts);
 
   return timetable;