Update constraint_engine.py

constraint_engine.py

@@ -37,7 +37,6 @@ class ConstraintEngine:
         self._apply_stretch_constraints()
         self._apply_grouping_constraints()
         self._apply_daily_subject_limit()
-        self._apply_no_first_hour_free()
 
     def _create_task_variables(self):
         for task in self.tasks:
@@ -315,35 +314,3 @@ class ConstraintEngine:
                     for lit in at_slot: self.model.AddImplication(is_active.Not(), lit.Not())
                     literals.append(is_active)
                 self.model.Add(sum(literals) <= self.max_continuous_stretch)
-
-    def _apply_no_first_hour_free(self):
-        """
-        HARD CONSTRAINT:
-        Ensures that the first hour (slot 0) of every day is never free for any section.
-        Every section must have at least one class starting at slot 0 every day.
-        """
-        from collections import defaultdict
-        import constants as const
-        
-        tasks_by_sec = defaultdict(list)
-        for task in self.tasks:
-            tasks_by_sec[task.section.section_id].append(task)
-
-        for sec_id, sec_tasks in tasks_by_sec.items():
-            if not sec_tasks: continue
-
-            for day in range(const.NUM_WORKING_DAYS):
-                first_slot = day * const.NUM_TEACHING_SLOTS_PER_DAY
-                
-                starts_at_first = []
-                for task in sec_tasks:
-                    start_var = self.task_vars[task.task_id][0]
-                    # We create a boolean variable that is True if start_var == first_slot
-                    at_first = self.model.NewBoolVar(f"hard_at1st_{task.task_id}_d{day}")
-                    self.model.Add(start_var == first_slot).OnlyEnforceIf(at_first)
-                    self.model.Add(start_var != first_slot).OnlyEnforceIf(at_first.Not())
-                    starts_at_first.append(at_first)
-
-                if starts_at_first:
-                    # At least one task MUST start at the first slot
-                    self.model.AddBoolOr(starts_at_first)