重构代码以提高性能的任何其他方法

Question

代码重构以提高性能

我有一个从数据库中获取的所有部门的清单 现在，我想根据某些条件从部门列表中获取所有合格部门

下面是将为每个部门循环的代码，并使用转换案例检查条件是否匹配，然后将该部门添加到符合条件的部门列表中

        List<EligibleDepartments> eligibleDepartments = new List<EligibleDepartments>();

        //use the following boolean values for eliminating common logic execution again and again
        bool IsCriteriaForABCDMatchSet = false;
        bool IsCriteriaForEFMatchSet = false;

        foreach (var department in departmentTypes) // here departmentTypes is the list of departments fetched from database
        {
            switch (department.DepartmentTypeId)
            {
                // here DepartmentTypes is the enum 
                case (int)DepartmentTypes.DepartmentA: 
                case (int)DepartmentTypes.DepartmentB:
                case (int)DepartmentTypes.DepartmentC:
                case (int)DepartmentTypes.DepartmentD:                   
                    if (IsCriteriaForABCDMatchSet || IsCriteriaForABCDMatches(students))
                    {
                        eligibleDepartments.Add(department);
                        IsCriteriaForABCDMatchSet = true;
                    }
                    break;
                case (int)DepartmentTypes.DepartmentE:
                case (int)DepartmentTypes.DepartmentF:
                    if (IsCriteriaForEFMatchesSet || IsCriteriaForEFMatches(students))
                    {
                        eligibleDepartments.Add(department);
                        IsCriteriaForEFMatchSet = true;
                    }
                    break;
                case (int)DepartmentTypes.DepartmentG:
                    if (IsCriteriaForGMatches(students))
                    {
                        eligibleDepartments.Add(department);
                    }
                    break;
                case (int)DepartmentTypes.DepartmentH:
                    if (IsCriteriaForIMatches(students))
                    {
                        eligibleDepartments.Add(department);
                    }
                    break;
                case (int)DepartmentTypes.DepartmentI:
                    if (IsCriteriaForIMatches(students))
                    {
                        eligibleDepartments.Add(department);
                    }
                    break;
                case (int)DepartmentTypes.DepartmentJ:
                    if (IsCriteriaForJMatches(students))
                    {
                        eligibleDepartments.Add(department);
                    }
                    break;
                case (int)DepartmentTypes.DepartmentK:
                    if (IsCriteriaForKMatches(students))
                    {
                        eligibleDepartments.Add(department);
                    }
                    break;
            }
        }

但是以某种方式我觉得这段代码会降低性能。 有什么替代的方法来重构此代码，并避免在此处使用切换用例。 任何帮助，将不胜感激。