diff --git a/judge/admin/contest.py b/judge/admin/contest.py
index f815016..1726d88 100644
--- a/judge/admin/contest.py
+++ b/judge/admin/contest.py
@@ -7,10 +7,12 @@ from django.forms import ModelForm, ModelMultipleChoiceField
 from django.http import Http404, HttpResponseRedirect
 from django.shortcuts import get_object_or_404
 from django.urls import reverse, reverse_lazy
+from django.utils import timezone
 from django.utils.html import format_html
 from django.utils.translation import gettext_lazy as _, ungettext
 from reversion.admin import VersionAdmin
 
+from django_ace import AceWidget
 from judge.models import Contest, ContestProblem, ContestSubmission, Profile, Rating
 from judge.ratings import rate_contest
 from judge.widgets import AdminHeavySelect2MultipleWidget, AdminHeavySelect2Widget, AdminPagedownWidget, \
@@ -94,7 +96,9 @@ class ContestForm(ModelForm):
 
     class Meta:
         widgets = {
-            'organizers': AdminHeavySelect2MultipleWidget(data_view='profile_select2'),
+            'authors': AdminHeavySelect2MultipleWidget(data_view='profile_select2'),
+            'curators': AdminHeavySelect2MultipleWidget(data_view='profile_select2'),
+            'testers': AdminHeavySelect2MultipleWidget(data_view='profile_select2'),
             'private_contestants': AdminHeavySelect2MultipleWidget(data_view='profile_select2',
                                                                    attrs={'style': 'width: 100%'}),
             'organizations': AdminHeavySelect2MultipleWidget(data_view='organization_select2'),
@@ -111,18 +115,19 @@ class ContestForm(ModelForm):
 
 class ContestAdmin(VersionAdmin):
     fieldsets = (
-        (None, {'fields': ('key', 'name', 'organizers')}),
-        (_('Settings'), {'fields': ('is_visible', 'use_clarifications', 'hide_problem_tags', 'hide_scoreboard',
+        (None, {'fields': ('key', 'name', 'authors', 'curators', 'testers')}),
+        (_('Settings'), {'fields': ('is_visible', 'use_clarifications', 'hide_problem_tags', 'scoreboard_visibility',
                                     'run_pretests_only', 'points_precision')}),
         (_('Scheduling'), {'fields': ('start_time', 'end_time', 'time_limit')}),
         (_('Details'), {'fields': ('description', 'og_image', 'logo_override_image', 'tags', 'summary')}),
-        (_('Format'), {'fields': ('format_name', 'format_config')}),
+        (_('Format'), {'fields': ('format_name', 'format_config', 'problem_label_script')}),
         (_('Rating'), {'fields': ('is_rated', 'rate_all', 'rating_floor', 'rating_ceiling', 'rate_exclude')}),
         (_('Access'), {'fields': ('access_code', 'is_private', 'private_contestants', 'is_organization_private',
                                   'organizations', 'view_contest_scoreboard')}),
         (_('Justice'), {'fields': ('banned_users',)}),
     )
     list_display = ('key', 'name', 'is_visible', 'is_rated', 'start_time', 'end_time', 'time_limit', 'user_count')
+    search_fields = ('key', 'name')
     inlines = [ContestProblemInline]
     actions_on_top = True
     actions_on_bottom = True
@@ -146,7 +151,7 @@ class ContestAdmin(VersionAdmin):
         if request.user.has_perm('judge.edit_all_contest'):
             return queryset
         else:
-            return queryset.filter(organizers__id=request.profile.id)
+            return queryset.filter(Q(authors=request.profile) | Q(curators=request.profile)).distinct()
 
     def get_readonly_fields(self, request, obj=None):
         readonly = []
@@ -158,6 +163,8 @@ class ContestAdmin(VersionAdmin):
             readonly += ['is_private', 'private_contestants', 'is_organization_private', 'organizations']
             if not request.user.has_perm('judge.change_contest_visibility'):
                 readonly += ['is_visible']
+        if not request.user.has_perm('judge.contest_problem_label'):
+            readonly += ['problem_label_script']
         return readonly
 
     def save_model(self, request, obj, form, change):
@@ -185,9 +192,9 @@ class ContestAdmin(VersionAdmin):
     def has_change_permission(self, request, obj=None):
         if not request.user.has_perm('judge.edit_own_contest'):
             return False
-        if request.user.has_perm('judge.edit_all_contest') or obj is None:
+        if obj is None:
             return True
-        return obj.organizers.filter(id=request.profile.id).exists()
+        return obj.is_editable_by(request.user)
 
     def _rescore(self, contest_key):
         from judge.tasks import rescore_contest
@@ -232,14 +239,10 @@ class ContestAdmin(VersionAdmin):
         if not request.user.has_perm('judge.contest_rating'):
             raise PermissionDenied()
         with transaction.atomic():
-            if connection.vendor == 'sqlite':
-                Rating.objects.all().delete()
-            else:
-                cursor = connection.cursor()
+            with connection.cursor() as cursor:
                 cursor.execute('TRUNCATE TABLE `%s`' % Rating._meta.db_table)
-                cursor.close()
             Profile.objects.update(rating=None)
-            for contest in Contest.objects.filter(is_rated=True).order_by('end_time'):
+            for contest in Contest.objects.filter(is_rated=True, end_time__lte=timezone.now()).order_by('end_time'):
                 rate_contest(contest)
         return HttpResponseRedirect(reverse('admin:judge_contest_changelist'))
 
@@ -247,16 +250,21 @@ class ContestAdmin(VersionAdmin):
         if not request.user.has_perm('judge.contest_rating'):
             raise PermissionDenied()
         contest = get_object_or_404(Contest, id=id)
-        if not contest.is_rated:
+        if not contest.is_rated or not contest.ended:
             raise Http404()
         with transaction.atomic():
             contest.rate()
         return HttpResponseRedirect(request.META.get('HTTP_REFERER', reverse('admin:judge_contest_changelist')))
 
-    def get_form(self, *args, **kwargs):
-        form = super(ContestAdmin, self).get_form(*args, **kwargs)
+    def get_form(self, request, obj=None, **kwargs):
+        form = super(ContestAdmin, self).get_form(request, obj, **kwargs)
+        if 'problem_label_script' in form.base_fields:
+            # form.base_fields['problem_label_script'] does not exist when the user has only view permission
+            # on the model.
+            form.base_fields['problem_label_script'].widget = AceWidget('lua', request.profile.ace_theme)
+   
         perms = ('edit_own_contest', 'edit_all_contest')
-        form.base_fields['organizers'].queryset = Profile.objects.filter(
+        form.base_fields['curators'].queryset = Profile.objects.filter(
             Q(user__is_superuser=True) |
             Q(user__groups__permissions__codename__in=perms) |
             Q(user__user_permissions__codename__in=perms),
diff --git a/judge/contest_format/base.py b/judge/contest_format/base.py
index 7fcadc3..d4e6e6f 100644
--- a/judge/contest_format/base.py
+++ b/judge/contest_format/base.py
@@ -82,6 +82,14 @@ class BaseContestFormat(six.with_metaclass(ABCMeta)):
         """
         raise NotImplementedError()
 
+    @abstractmethod
+    def get_contest_problem_label_script(self):
+        """
+        Returns the default Lua script to generate contest problem labels.
+        :return: A string, the Lua script.
+        """
+        raise NotImplementedError()
+
     @classmethod
     def best_solution_state(cls, points, total):
         if not points:
diff --git a/judge/contest_format/default.py b/judge/contest_format/default.py
index 690cdfc..a3c9c0b 100644
--- a/judge/contest_format/default.py
+++ b/judge/contest_format/default.py
@@ -68,3 +68,10 @@ class DefaultContestFormat(BaseContestFormat):
 
     def get_problem_breakdown(self, participation, contest_problems):
         return [(participation.format_data or {}).get(str(contest_problem.id)) for contest_problem in contest_problems]
+
+    def get_contest_problem_label_script(self):
+        return '''
+            function(n)
+                return tostring(math.floor(n + 1))
+            end
+        '''
\ No newline at end of file
diff --git a/judge/contest_format/icpc.py b/judge/contest_format/icpc.py
new file mode 100644
index 0000000..0c545fc
--- /dev/null
+++ b/judge/contest_format/icpc.py
@@ -0,0 +1,129 @@
+from datetime import timedelta
+
+from django.core.exceptions import ValidationError
+from django.db import connection
+from django.template.defaultfilters import floatformat
+from django.urls import reverse
+from django.utils.html import format_html
+from django.utils.safestring import mark_safe
+from django.utils.translation import gettext_lazy
+
+from judge.contest_format.default import DefaultContestFormat
+from judge.contest_format.registry import register_contest_format
+from judge.timezone import from_database_time
+from judge.utils.timedelta import nice_repr
+
+
+@register_contest_format('icpc')
+class ICPCContestFormat(DefaultContestFormat):
+    name = gettext_lazy('ICPC')
+    config_defaults = {'penalty': 20}
+    config_validators = {'penalty': lambda x: x >= 0}
+    '''
+        penalty: Number of penalty minutes each incorrect submission adds. Defaults to 20.
+    '''
+
+    @classmethod
+    def validate(cls, config):
+        if config is None:
+            return
+
+        if not isinstance(config, dict):
+            raise ValidationError('ICPC-styled contest expects no config or dict as config')
+
+        for key, value in config.items():
+            if key not in cls.config_defaults:
+                raise ValidationError('unknown config key "%s"' % key)
+            if not isinstance(value, type(cls.config_defaults[key])):
+                raise ValidationError('invalid type for config key "%s"' % key)
+            if not cls.config_validators[key](value):
+                raise ValidationError('invalid value "%s" for config key "%s"' % (value, key))
+
+    def __init__(self, contest, config):
+        self.config = self.config_defaults.copy()
+        self.config.update(config or {})
+        self.contest = contest
+
+    def update_participation(self, participation):
+        cumtime = 0
+        last = 0
+        penalty = 0
+        score = 0
+        format_data = {}
+
+        with connection.cursor() as cursor:
+            cursor.execute('''
+                SELECT MAX(cs.points) as `points`, (
+                    SELECT MIN(csub.date)
+                        FROM judge_contestsubmission ccs LEFT OUTER JOIN
+                             judge_submission csub ON (csub.id = ccs.submission_id)
+                        WHERE ccs.problem_id = cp.id AND ccs.participation_id = %s AND ccs.points = MAX(cs.points)
+                ) AS `time`, cp.id AS `prob`
+                FROM judge_contestproblem cp INNER JOIN
+                     judge_contestsubmission cs ON (cs.problem_id = cp.id AND cs.participation_id = %s) LEFT OUTER JOIN
+                     judge_submission sub ON (sub.id = cs.submission_id)
+                GROUP BY cp.id
+            ''', (participation.id, participation.id))
+
+            for points, time, prob in cursor.fetchall():
+                time = from_database_time(time)
+                dt = (time - participation.start).total_seconds()
+
+                # Compute penalty
+                if self.config['penalty']:
+                    # An IE can have a submission result of `None`
+                    subs = participation.submissions.exclude(submission__result__isnull=True) \
+                                                    .exclude(submission__result__in=['IE', 'CE']) \
+                                                    .filter(problem_id=prob)
+                    if points:
+                        prev = subs.filter(submission__date__lte=time).count() - 1
+                        penalty += prev * self.config['penalty'] * 60
+                    else:
+                        # We should always display the penalty, even if the user has a score of 0
+                        prev = subs.count()
+                else:
+                    prev = 0
+
+                if points:
+                    cumtime += dt
+                    last = max(last, dt)
+
+                format_data[str(prob)] = {'time': dt, 'points': points, 'penalty': prev}
+                score += points
+
+        participation.cumtime = cumtime + penalty
+        participation.score = score
+        participation.tiebreaker = last  # field is sorted from least to greatest
+        participation.format_data = format_data
+        participation.save()
+
+    def display_user_problem(self, participation, contest_problem):
+        format_data = (participation.format_data or {}).get(str(contest_problem.id))
+        if format_data:
+            penalty = format_html('<small style="color:red"> ({penalty})</small>',
+                                  penalty=floatformat(format_data['penalty'])) if format_data['penalty'] else ''
+            return format_html(
+                '<td class="{state}"><a href="{url}">{points}{penalty}<div class="solving-time">{time}</div></a></td>',
+                state=(('pretest-' if self.contest.run_pretests_only and contest_problem.is_pretested else '') +
+                       self.best_solution_state(format_data['points'], contest_problem.points)),
+                url=reverse('contest_user_submissions',
+                            args=[self.contest.key, participation.user.user.username, contest_problem.problem.code]),
+                points=floatformat(format_data['points']),
+                penalty=penalty,
+                time=nice_repr(timedelta(seconds=format_data['time']), 'noday'),
+            )
+        else:
+            return mark_safe('<td></td>')
+
+    def get_contest_problem_label_script(self):
+        return '''
+            function(n)
+                n = n + 1
+                ret = ""
+                while n > 0 do
+                    ret = string.char((n - 1) % 26 + 65) .. ret
+                    n = math.floor((n - 1) / 26)
+                end
+                return ret
+            end
+        '''
\ No newline at end of file
diff --git a/judge/migrations/0115_auto_20210525_0222.py b/judge/migrations/0115_auto_20210525_0222.py
new file mode 100644
index 0000000..91312de
--- /dev/null
+++ b/judge/migrations/0115_auto_20210525_0222.py
@@ -0,0 +1,63 @@
+# Generated by Django 2.2.17 on 2021-05-24 19:22
+
+from django.db import migrations, models
+
+def hide_scoreboard_eq_true(apps, schema_editor):
+    Contest = apps.get_model('judge', 'Contest')
+    Contest.objects.filter(hide_scoreboard=True).update(scoreboard_visibility='C')
+
+
+def scoreboard_visibility_eq_contest(apps, schema_editor):
+    Contest = apps.get_model('judge', 'Contest')
+    Contest.objects.filter(scoreboard_visibility__in=('C', 'P')).update(hide_scoreboard=True)
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('judge', '0114_auto_20201228_1041'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='contest',
+            options={'permissions': (('see_private_contest', 'See private contests'), ('edit_own_contest', 'Edit own contests'), ('edit_all_contest', 'Edit all contests'), ('clone_contest', 'Clone contest'), ('moss_contest', 'MOSS contest'), ('contest_rating', 'Rate contests'), ('contest_access_code', 'Contest access codes'), ('create_private_contest', 'Create private contests'), ('change_contest_visibility', 'Change contest visibility'), ('contest_problem_label', 'Edit contest problem label script')), 'verbose_name': 'contest', 'verbose_name_plural': 'contests'},
+        ),
+        migrations.RemoveField(
+            model_name='contest',
+            name='hide_scoreboard',
+        ),
+        migrations.RemoveField(
+            model_name='contest',
+            name='organizers',
+        ),
+        migrations.AddField(
+            model_name='contest',
+            name='authors',
+            field=models.ManyToManyField(help_text='These users will be able to edit the contest.', related_name='_contest_authors_+', to='judge.Profile'),
+        ),
+        migrations.AddField(
+            model_name='contest',
+            name='curators',
+            field=models.ManyToManyField(blank=True, help_text='These users will be able to edit the contest, but will not be listed as authors.', related_name='_contest_curators_+', to='judge.Profile'),
+        ),
+        migrations.AddField(
+            model_name='contest',
+            name='problem_label_script',
+            field=models.TextField(blank=True, help_text='A custom Lua function to generate problem labels. Requires a single function with an integer parameter, the zero-indexed contest problem index, and returns a string, the label.', verbose_name='contest problem label script'),
+        ),
+        migrations.AddField(
+            model_name='contest',
+            name='scoreboard_visibility',
+            field=models.CharField(choices=[('V', 'Visible'), ('C', 'Hidden for duration of contest'), ('P', 'Hidden for duration of participation')], default='V', help_text='Scoreboard visibility through the duration of the contest', max_length=1, verbose_name='scoreboard visibility'),
+        ),
+        migrations.AddField(
+            model_name='contest',
+            name='testers',
+            field=models.ManyToManyField(blank=True, help_text='These users will be able to view the contest, but not edit it.', related_name='_contest_testers_+', to='judge.Profile'),
+        ),
+        migrations.AddField(
+            model_name='contestparticipation',
+            name='tiebreaker',
+            field=models.FloatField(default=0.0, verbose_name='tie-breaking field'),
+        ),
+    ]
diff --git a/judge/models/contest.py b/judge/models/contest.py
index 939e06d..46a6e06 100644
--- a/judge/models/contest.py
+++ b/judge/models/contest.py
@@ -1,12 +1,13 @@
 from django.core.exceptions import ValidationError
 from django.core.validators import MaxValueValidator, MinValueValidator, RegexValidator
 from django.db import models, transaction
-from django.db.models import CASCADE
+from django.db.models import CASCADE, Q
 from django.urls import reverse
 from django.utils import timezone
 from django.utils.functional import cached_property
 from django.utils.translation import gettext, gettext_lazy as _
 from jsonfield import JSONField
+from lupa import LuaRuntime
 from moss import MOSS_LANG_C, MOSS_LANG_CC, MOSS_LANG_JAVA, MOSS_LANG_PYTHON, MOSS_LANG_PASCAL
 
 from judge import contest_format
@@ -48,11 +49,25 @@ class ContestTag(models.Model):
 
 
 class Contest(models.Model):
+    SCOREBOARD_VISIBLE = 'V'
+    SCOREBOARD_AFTER_CONTEST = 'C'
+    SCOREBOARD_AFTER_PARTICIPATION = 'P'
+    SCOREBOARD_VISIBILITY = (
+        (SCOREBOARD_VISIBLE, _('Visible')),
+        (SCOREBOARD_AFTER_CONTEST, _('Hidden for duration of contest')),
+        (SCOREBOARD_AFTER_PARTICIPATION, _('Hidden for duration of participation')),
+    )
     key = models.CharField(max_length=20, verbose_name=_('contest id'), unique=True,
                            validators=[RegexValidator('^[a-z0-9]+$', _('Contest id must be ^[a-z0-9]+$'))])
     name = models.CharField(max_length=100, verbose_name=_('contest name'), db_index=True)
-    organizers = models.ManyToManyField(Profile, help_text=_('These people will be able to edit the contest.'),
-                                        related_name='organizers+')
+    authors = models.ManyToManyField(Profile, help_text=_('These users will be able to edit the contest.'),
+                                         related_name='authors+')
+    curators = models.ManyToManyField(Profile, help_text=_('These users will be able to edit the contest, '
+                                                           'but will not be listed as authors.'),
+                                      related_name='curators+', blank=True)
+    testers = models.ManyToManyField(Profile, help_text=_('These users will be able to view the contest, '
+                                                          'but not edit it.'),
+                                     blank=True, related_name='testers+')
     description = models.TextField(verbose_name=_('description'), blank=True)
     problems = models.ManyToManyField(Problem, verbose_name=_('problems'), through='ContestProblem')
     start_time = models.DateTimeField(verbose_name=_('start time'), db_index=True)
@@ -64,10 +79,9 @@ class Contest(models.Model):
                                                  'specified organizations.'))
     is_rated = models.BooleanField(verbose_name=_('contest rated'), help_text=_('Whether this contest can be rated.'),
                                    default=False)
-    hide_scoreboard = models.BooleanField(verbose_name=_('hide scoreboard'),
-                                          help_text=_('Whether the scoreboard should remain hidden for the duration '
-                                                      'of the contest.'),
-                                          default=False)
+    scoreboard_visibility = models.CharField(verbose_name=_('scoreboard visibility'), default=SCOREBOARD_VISIBLE,
+                                             max_length=1, help_text=_('Scoreboard visibility through the duration '
+                                                                       'of the contest'), choices=SCOREBOARD_VISIBILITY)
     view_contest_scoreboard = models.ManyToManyField(Profile, verbose_name=_('view contest scoreboard'), blank=True,
                                                      related_name='view_contest_scoreboard',
                                                      help_text=_('These users will be able to view the scoreboard.'))
@@ -116,6 +130,10 @@ class Contest(models.Model):
                               help_text=_('A JSON object to serve as the configuration for the chosen contest format '
                                           'module. Leave empty to use None. Exact format depends on the contest format '
                                           'selected.'))
+    problem_label_script = models.TextField(verbose_name='contest problem label script', blank=True,
+                                            help_text='A custom Lua function to generate problem labels. Requires a '
+                                                      'single function with an integer parameter, the zero-indexed '
+                                                      'contest problem index, and returns a string, the label.')
     points_precision = models.IntegerField(verbose_name=_('precision points'), default=2,
                                            validators=[MinValueValidator(0), MaxValueValidator(10)],
                                            help_text=_('Number of digits to round points to.'))
@@ -128,30 +146,72 @@ class Contest(models.Model):
     def format(self):
         return self.format_class(self, self.format_config)
 
+    @cached_property
+    def get_label_for_problem(self):
+        def DENY_ALL(obj, attr_name, is_setting):
+            raise AttributeError()
+        lua = LuaRuntime(attribute_filter=DENY_ALL, register_eval=False, register_builtins=False)
+        return lua.eval(self.problem_label_script or self.format.get_contest_problem_label_script())
+
     def clean(self):
         # Django will complain if you didn't fill in start_time or end_time, so we don't have to.
         if self.start_time and self.end_time and self.start_time >= self.end_time:
             raise ValidationError('What is this? A contest that ended before it starts?')
         self.format_class.validate(self.format_config)
 
+        try:
+            # a contest should have at least one problem, with contest problem index 0
+            # so test it to see if the script returns a valid label.
+            label = self.get_label_for_problem(0)
+        except Exception as e:
+            raise ValidationError('Contest problem label script: %s' % e)
+        else:
+            if not isinstance(label, str):
+                raise ValidationError('Contest problem label script: script should return a string.')
+
     def is_in_contest(self, user):
         if user.is_authenticated:
             profile = user.profile
             return profile and profile.current_contest is not None and profile.current_contest.contest == self
         return False
 
-    def can_see_scoreboard(self, user):
-        if user.has_perm('judge.see_private_contest'):
+    def can_see_own_scoreboard(self, user):
+        if self.can_see_full_scoreboard(user):
             return True
-        if user.is_authenticated and self.organizers.filter(id=user.profile.id).exists():
-            return True
-        if user.is_authenticated and self.view_contest_scoreboard.filter(id=user.profile.id).exists():
-            return True
-        if not self.is_visible:
+        if not self.can_join:
             return False
-        if self.start_time is not None and self.start_time > timezone.now():
+        if not self.show_scoreboard and not self.is_in_contest(user):
             return False
-        if self.hide_scoreboard and not self.is_in_contest(user) and self.end_time > timezone.now():
+        return True
+
+    def can_see_full_scoreboard(self, user):
+        if self.show_scoreboard:
+            return True
+        if not user.is_authenticated:
+            return False
+        if user.has_perm('judge.see_private_contest') or user.has_perm('judge.edit_all_contest'):
+            return True
+        if user.profile.id in self.editor_ids:
+            return True
+        if self.view_contest_scoreboard.filter(id=user.profile.id).exists():
+            return True
+        if self.scoreboard_visibility == self.SCOREBOARD_AFTER_PARTICIPATION and self.has_completed_contest(user):
+            return True
+        return False
+
+    def has_completed_contest(self, user):
+        if user.is_authenticated:
+            participation = self.users.filter(virtual=ContestParticipation.LIVE, user=user.profile).first()
+            if participation and participation.ended:
+                return True
+        return False
+
+    @cached_property
+    def show_scoreboard(self):
+        if not self.can_join:
+            return False
+        if (self.scoreboard_visibility in (self.SCOREBOARD_AFTER_CONTEST, self.SCOREBOARD_AFTER_PARTICIPATION) and
+                not self.ended):
             return False
         return True
 
@@ -186,6 +246,19 @@ class Contest(models.Model):
     def ended(self):
         return self.end_time < self._now
 
+    @cached_property
+    def author_ids(self):
+        return Contest.authors.through.objects.filter(contest=self).values_list('profile_id', flat=True)
+
+    @cached_property
+    def editor_ids(self):
+        return self.author_ids.union(
+            Contest.curators.through.objects.filter(contest=self).values_list('profile_id', flat=True))
+
+    @cached_property
+    def tester_ids(self):
+        return Contest.testers.through.objects.filter(contest=self).values_list('profile_id', flat=True)
+
     def __str__(self):
         return self.name
 
@@ -198,50 +271,111 @@ class Contest(models.Model):
 
     update_user_count.alters_data = True
 
-    @cached_property
-    def show_scoreboard(self):
-        if self.hide_scoreboard and not self.ended:
-            return False
-        return True
+    class Inaccessible(Exception):
+        pass
+
+    class PrivateContest(Exception):
+        pass
+
+    def access_check(self, user):
+        # Do unauthenticated check here so we can skip authentication checks later on.
+        if not user.is_authenticated:
+            # Unauthenticated users can only see visible, non-private contests
+            if not self.is_visible:
+                raise self.Inaccessible()
+            if self.is_private or self.is_organization_private:
+                raise self.PrivateContest()
+            return
+
+        # If the user can view or edit all contests
+        if user.has_perm('judge.see_private_contest') or user.has_perm('judge.edit_all_contest'):
+            return
+
+        # User is organizer or curator for contest
+        if user.profile.id in self.editor_ids:
+            return
+
+        # User is tester for contest
+        if user.profile.id in self.tester_ids:
+            return
+
+        # Contest is not publicly visible
+        if not self.is_visible:
+            raise self.Inaccessible()
+
+        # Contest is not private
+        if not self.is_private and not self.is_organization_private:
+            return
+
+        if self.view_contest_scoreboard.filter(id=user.profile.id).exists():
+            return
+            
+        in_org = self.organizations.filter(id__in=user.profile.organizations.all()).exists()
+        in_users = self.private_contestants.filter(id=user.profile.id).exists()
+
+        if not self.is_private and self.is_organization_private:
+            if in_org:
+                return
+            raise self.PrivateContest()    
+
+        if self.is_private and not self.is_organization_private:
+            if in_users:
+                return
+            raise self.PrivateContest()
+
+        if self.is_private and self.is_organization_private:
+            if in_org and in_users:
+                return
+            raise self.PrivateContest()
 
     def is_accessible_by(self, user):
-        # Contest is publicly visible
-        if self.is_visible:
-            # Contest is not private
-            if not self.is_private and not self.is_organization_private:
-                return True
-            if user.is_authenticated:
-                # User is in the organizations it is private to
-                if self.organizations.filter(id__in=user.profile.organizations.all()).exists():
-                    return True
-                # User is in the group of private contestants
-                if self.private_contestants.filter(id=user.profile.id).exists():
-                    return True
-                if self.view_contest_scoreboard.filter(id=user.profile.id).exists():
-                    return True
-
-        # If the user can view all contests
-        if user.has_perm('judge.see_private_contest'):
+        try:
+            self.access_check(user)
+        except (self.Inaccessible, self.PrivateContest):
+            return False
+        else:
             return True
 
-        # User can edit the contest
-        return self.is_editable_by(user)
-
     def is_editable_by(self, user):
         # If the user can edit all contests
         if user.has_perm('judge.edit_all_contest'):
             return True
 
-        # If the user is a contest organizer
-        if user.has_perm('judge.edit_own_contest') and \
-                self.organizers.filter(id=user.profile.id).exists():
+        # If the user is a contest organizer or curator
+        if user.has_perm('judge.edit_own_contest') and user.profile.id in self.editor_ids:
             return True
 
         return False
 
+    @classmethod
+    def get_visible_contests(cls, user):
+        if not user.is_authenticated:
+            return cls.objects.filter(is_visible=True, is_organization_private=False, is_private=False) \
+                              .defer('description').distinct()
+
+        queryset = cls.objects.defer('description')
+        if not (user.has_perm('judge.see_private_contest') or user.has_perm('judge.edit_all_contest')):
+            q = Q(is_visible=True)
+            q &= (
+                Q(view_contest_scoreboard=user.profile) |
+                Q(is_organization_private=False, is_private=False) |
+                Q(is_organization_private=False, is_private=True, private_contestants=user.profile) |
+                Q(is_organization_private=True, is_private=False, organizations__in=user.profile.organizations.all()) |
+                Q(is_organization_private=True, is_private=True, organizations__in=user.profile.organizations.all(),
+                  private_contestants=user.profile)
+            )
+
+            q |= Q(authors=user.profile)
+            q |= Q(curators=user.profile)
+            q |= Q(testers=user.profile)
+            queryset = queryset.filter(q)
+        return queryset.distinct()
+
     def rate(self):
-        Rating.objects.filter(contest__end_time__gte=self.end_time).delete()
-        for contest in Contest.objects.filter(is_rated=True, end_time__gte=self.end_time).order_by('end_time'):
+        Rating.objects.filter(contest__end_time__range=(self.end_time, self._now)).delete()
+        for contest in Contest.objects.filter(
+            is_rated=True, end_time__range=(self.end_time, self._now),
+        ).order_by('end_time'):
             rate_contest(contest)
 
     class Meta:
@@ -255,6 +389,7 @@ class Contest(models.Model):
             ('contest_access_code', _('Contest access codes')),
             ('create_private_contest', _('Create private contests')),
             ('change_contest_visibility', _('Change contest visibility')),
+            ('contest_problem_label', _('Edit contest problem label script')),
         )
         verbose_name = _('contest')
         verbose_name_plural = _('contests')
@@ -271,6 +406,7 @@ class ContestParticipation(models.Model):
     cumtime = models.PositiveIntegerField(verbose_name=_('cumulative time'), default=0)
     is_disqualified = models.BooleanField(verbose_name=_('is disqualified'), default=False,
                                           help_text=_('Whether this participation is disqualified.'))
+    tiebreaker = models.FloatField(verbose_name=_('tie-breaking field'), default=0.0)
     virtual = models.IntegerField(verbose_name=_('virtual participation id'), default=LIVE,
                                   help_text=_('0 means non-virtual, otherwise the n-th virtual participation.'))
     format_data = JSONField(verbose_name=_('contest format specific data'), null=True, blank=True)
diff --git a/judge/models/problem.py b/judge/models/problem.py
index a469ef6..3dac05b 100644
--- a/judge/models/problem.py
+++ b/judge/models/problem.py
@@ -5,7 +5,7 @@ from django.contrib.contenttypes.fields import GenericRelation
 from django.core.cache import cache
 from django.core.validators import MaxValueValidator, MinValueValidator, RegexValidator
 from django.db import models
-from django.db.models import CASCADE, F, QuerySet, SET_NULL
+from django.db.models import CASCADE, F, Q, QuerySet, SET_NULL
 from django.db.models.expressions import RawSQL
 from django.db.models.functions import Coalesce
 from django.urls import reverse
@@ -219,6 +219,43 @@ class Problem(models.Model):
 
     def is_subs_manageable_by(self, user):
         return user.is_staff and user.has_perm('judge.rejudge_submission') and self.is_editable_by(user)
+    
+    @classmethod
+    def get_visible_problems(cls, user):
+        # Do unauthenticated check here so we can skip authentication checks later on.
+        if not user.is_authenticated:
+            return cls.get_public_problems()
+
+        # Conditions for visible problem:
+        #   - `judge.edit_all_problem` or `judge.see_private_problem`
+        #   - otherwise
+        #       - not is_public problems
+        #           - author or curator or tester
+        #       - is_public problems
+        #           - not is_organization_private or in organization or `judge.see_organization_problem`
+        #           - author or curator or tester
+        queryset = cls.objects.defer('description')
+
+        if not (user.has_perm('judge.see_private_problem') or user.has_perm('judge.edit_all_problem')):
+            q = Q(is_public=True)
+            if not user.has_perm('judge.see_organization_problem'):
+                # Either not organization private or in the organization.
+                q &= (
+                    Q(is_organization_private=False) |
+                    Q(is_organization_private=True, organizations__in=user.profile.organizations.all())
+                )
+
+            # Authors, curators, and testers should always have access, so OR at the very end.
+            q |= Q(authors=user.profile)
+            q |= Q(curators=user.profile)
+            q |= Q(testers=user.profile)
+            queryset = queryset.filter(q)
+
+        return queryset.distinct()
+
+    @classmethod
+    def get_public_problems(cls):
+        return cls.objects.filter(is_public=True, is_organization_private=False).defer('description').distinct()
 
     def __str__(self):
         return self.name
diff --git a/judge/models/profile.py b/judge/models/profile.py
index 2fb51a3..b3c5fa0 100644
--- a/judge/models/profile.py
+++ b/judge/models/profile.py
@@ -136,12 +136,15 @@ class Profile(models.Model):
 
     def calculate_points(self, table=_pp_table):
         from judge.models import Problem
-        data = (Problem.objects.filter(submission__user=self, submission__points__isnull=False, is_public=True,
-                                       is_organization_private=False)
-                       .annotate(max_points=Max('submission__points')).order_by('-max_points')
-                       .values_list('max_points', flat=True).filter(max_points__gt=0))
-        extradata = Problem.objects.filter(submission__user=self, submission__result='AC', is_public=True) \
-                           .values('id').distinct().count()
+        public_problems = Problem.get_public_problems()
+        data = (
+            public_problems.filter(submission__user=self, submission__points__isnull=False)
+                           .annotate(max_points=Max('submission__points')).order_by('-max_points')
+                           .values_list('max_points', flat=True).filter(max_points__gt=0)
+        )
+        extradata = (
+            public_problems.filter(submission__user=self, submission__result='AC').values('id').count()
+        )
         bonus_function = settings.DMOJ_PP_BONUS_FUNCTION
         points = sum(data)
         problems = len(data)
diff --git a/judge/sitemap.py b/judge/sitemap.py
index 6ae8657..2deea97 100644
--- a/judge/sitemap.py
+++ b/judge/sitemap.py
@@ -11,7 +11,7 @@ class ProblemSitemap(Sitemap):
     priority = 0.8
 
     def items(self):
-        return Problem.objects.filter(is_public=True, is_organization_private=False).values_list('code')
+        return Problem.get_public_problems().values_list('code')
 
     def location(self, obj):
         return reverse('problem_detail', args=obj)
diff --git a/judge/tasks/__init__.py b/judge/tasks/__init__.py
index 22c5253..90fd6d3 100644
--- a/judge/tasks/__init__.py
+++ b/judge/tasks/__init__.py
@@ -1,3 +1,4 @@
+from judge.tasks.contest import *
 from judge.tasks.demo import *
 from judge.tasks.contest import *
 from judge.tasks.submission import *
diff --git a/judge/utils/problems.py b/judge/utils/problems.py
index f87f807..570035b 100644
--- a/judge/utils/problems.py
+++ b/judge/utils/problems.py
@@ -112,8 +112,8 @@ def hot_problems(duration, limit):
     cache_key = 'hot_problems:%d:%d' % (duration.total_seconds(), limit)
     qs = cache.get(cache_key)
     if qs is None:
-        qs = Problem.objects.filter(is_public=True, is_organization_private=False,
-                                    submission__date__gt=timezone.now() - duration, points__gt=3, points__lt=25)
+        qs = Problem.get_public_problems() \
+                    .filter(submission__date__gt=timezone.now() - duration, points__gt=3, points__lt=25)
         qs0 = qs.annotate(k=Count('submission__user', distinct=True)).order_by('-k').values_list('k', flat=True)
 
         if not qs0:
diff --git a/judge/views/api/api_v1.py b/judge/views/api/api_v1.py
index 93e7690..c67bf34 100644
--- a/judge/views/api/api_v1.py
+++ b/judge/views/api/api_v1.py
@@ -16,10 +16,9 @@ def sane_time_repr(delta):
 
 
 def api_v1_contest_list(request):
-    queryset = Contest.objects.filter(is_visible=True, is_private=False,
-                                      is_organization_private=False).prefetch_related(
-        Prefetch('tags', queryset=ContestTag.objects.only('name'), to_attr='tag_list')).defer('description')
-
+    queryset = Contest.get_visible_contests(request.user).prefetch_related(
+        Prefetch('tags', queryset=ContestTag.objects.only('name'), to_attr='tag_list'))
+    
     return JsonResponse({c.key: {
         'name': c.name,
         'start_time': c.start_time.isoformat(),
@@ -33,10 +32,7 @@ def api_v1_contest_detail(request, contest):
     contest = get_object_or_404(Contest, key=contest)
 
     in_contest = contest.is_in_contest(request.user)
-    can_see_rankings = contest.can_see_scoreboard(request.user)
-    if contest.hide_scoreboard and in_contest:
-        can_see_rankings = False
-
+    can_see_rankings = contest.can_see_full_scoreboard(request.user)
     problems = list(contest.contest_problems.select_related('problem')
                     .defer('problem__description').order_by('order'))
     participations = (contest.users.filter(virtual=0, user__is_unlisted=False)
diff --git a/judge/views/blog.py b/judge/views/blog.py
index 4244107..7c6cc11 100644
--- a/judge/views/blog.py
+++ b/judge/views/blog.py
@@ -81,17 +81,14 @@ class PostList(ListView):
                                                       .annotate(points=Max('points'), latest=Max('date'))
                                                       .order_by('-latest')
                                                       [:settings.DMOJ_BLOG_RECENTLY_ATTEMPTED_PROBLEMS_COUNT])
+        
+        visible_contests = Contest.get_visible_contests(self.request.user).filter(is_visible=True) \
+                                  .order_by('start_time')
 
-        visible_contests = Contest.objects.filter(is_visible=True).order_by('start_time')
-        q = Q(is_private=False, is_organization_private=False)
-        if self.request.user.is_authenticated:
-            q |= Q(is_organization_private=True, organizations__in=user.organizations.all())
-            q |= Q(is_private=True, private_contestants=user)
-            q |= Q(view_contest_scoreboard=user)
-        visible_contests = visible_contests.filter(q)
-        context['current_contests'] = visible_contests.filter(start_time__lte=now, end_time__gt=now).distinct()
-        context['future_contests'] = visible_contests.filter(start_time__gt=now).distinct()
+        context['current_contests'] = visible_contests.filter(start_time__lte=now, end_time__gt=now)
+        context['future_contests'] = visible_contests.filter(start_time__gt=now)
 
+        visible_contests = Contest.get_visible_contests(self.request.user).filter(is_visible=True)
         if self.request.user.is_authenticated:
             profile = self.request.profile
             context['own_open_tickets'] = (Ticket.objects.filter(Q(user=profile) | Q(assignees__in=[profile]), is_open=True).order_by('-id')
diff --git a/judge/views/contests.py b/judge/views/contests.py
index b68f137..9099e12 100644
--- a/judge/views/contests.py
+++ b/judge/views/contests.py
@@ -12,7 +12,7 @@ from django.contrib.auth.mixins import LoginRequiredMixin, PermissionRequiredMix
 from django.core.cache import cache
 from django.core.exceptions import ImproperlyConfigured, ObjectDoesNotExist
 from django.db import IntegrityError
-from django.db.models import Case, Count, FloatField, IntegerField, Max, Min, Q, Sum, Value, When
+from django.db.models import Case, Count, F, FloatField, IntegerField, Max, Min, Q, Sum, Value, When
 from django.db.models.expressions import CombinedExpression
 from django.http import Http404, HttpResponse, HttpResponseBadRequest, HttpResponseRedirect
 from django.shortcuts import get_object_or_404, render
@@ -59,20 +59,7 @@ def _find_contest(request, key, private_check=True):
 
 class ContestListMixin(object):
     def get_queryset(self):
-        queryset = Contest.objects.all()
-        if not self.request.user.has_perm('judge.see_private_contest'):
-            q = Q(is_visible=True)
-            if self.request.user.is_authenticated:
-                q |= Q(organizers=self.request.profile)
-            queryset = queryset.filter(q)
-        if not self.request.user.has_perm('judge.edit_all_contest'):
-            q = Q(is_private=False, is_organization_private=False)
-            if self.request.user.is_authenticated:
-                q |= Q(is_organization_private=True, organizations__in=self.request.profile.organizations.all())
-                q |= Q(is_private=True, private_contestants=self.request.profile)
-                q |= Q(view_contest_scoreboard=self.request.profile)
-            queryset = queryset.filter(q)
-        return queryset.distinct()
+        return Contest.get_visible_contests(self.request.user)
 
 
 class ContestList(DiggPaginatorMixin, TitleMixin, ContestListMixin, ListView):
@@ -101,7 +88,7 @@ class ContestList(DiggPaginatorMixin, TitleMixin, ContestListMixin, ListView):
 
     def _get_queryset(self):
         queryset = super(ContestList, self).get_queryset() \
-            .order_by('-start_time', 'key').prefetch_related('tags', 'organizations', 'organizers')
+            .order_by('-start_time', 'key').prefetch_related('tags', 'organizations', 'authors', 'curators', 'testers')
         
         if 'contest' in self.request.GET:
             self.contest_query = query = ' '.join(self.request.GET.getlist('contest')).strip()
@@ -128,7 +115,9 @@ class ContestList(DiggPaginatorMixin, TitleMixin, ContestListMixin, ListView):
         if self.request.user.is_authenticated:
             for participation in ContestParticipation.objects.filter(virtual=0, user=self.request.profile,
                                                                      contest_id__in=present) \
-                    .select_related('contest').prefetch_related('contest__organizers'):
+                    .select_related('contest') \
+                    .prefetch_related('contest__authors', 'contest__curators', 'contest__testers')\
+                    .annotate(key=F('contest__key')):
                 if not participation.ended:
                     active.append(participation)
                     present.remove(participation.contest)
@@ -164,37 +153,44 @@ class ContestMixin(object):
     slug_url_kwarg = 'contest'
 
     @cached_property
-    def is_organizer(self):
-        return self.check_organizer()
+    def is_editor(self):
+        if not self.request.user.is_authenticated:
+            return False
+        return self.request.profile.id in self.object.editor_ids
 
-    def check_organizer(self, contest=None, user=None):
-        if user is None:
-            user = self.request.user
-        return (contest or self.object).is_editable_by(user)
+    @cached_property
+    def is_tester(self):
+        if not self.request.user.is_authenticated:
+            return False
+        return self.request.profile.id in self.object.tester_ids
+    
+    @cached_property
+    def can_edit(self):
+        return self.object.is_editable_by(self.request.user)
 
     def get_context_data(self, **kwargs):
         context = super(ContestMixin, self).get_context_data(**kwargs)
         if self.request.user.is_authenticated:
-            profile = self.request.profile
-            in_contest = context['in_contest'] = (profile.current_contest is not None and
-                                                  profile.current_contest.contest == self.object)
-            if in_contest:
-                context['participation'] = profile.current_contest
-                context['participating'] = True
+            try:
+                context['live_participation'] = (
+                    self.request.profile.contest_history.get(
+                        contest=self.object,
+                        virtual=ContestParticipation.LIVE,
+                    )
+                )
+            except ContestParticipation.DoesNotExist:
+                context['live_participation'] = None
+                context['has_joined'] = False
             else:
-                try:
-                    context['participation'] = profile.contest_history.get(contest=self.object, virtual=0)
-                except ContestParticipation.DoesNotExist:
-                    context['participating'] = False
-                    context['participation'] = None
-                else:
-                    context['participating'] = True
+                context['has_joined'] = True
         else:
-            context['participating'] = False
-            context['participation'] = None
-            context['in_contest'] = False
+            context['live_participation'] = None
+            context['has_joined'] = False
+            
         context['now'] = timezone.now()
-        context['is_organizer'] = self.is_organizer
+        context['is_editor'] = self.is_editor
+        context['is_tester'] = self.is_tester
+        context['can_edit'] = self.can_edit
 
         if not self.object.og_image or not self.object.summary:
             metadata = generate_opengraph('generated-meta-contest:%d' % self.object.id,
@@ -210,18 +206,22 @@ class ContestMixin(object):
 
     def get_object(self, queryset=None):
         contest = super(ContestMixin, self).get_object(queryset)
-        user = self.request.user
         profile = self.request.profile
 
         if (profile is not None and
                 ContestParticipation.objects.filter(id=profile.current_contest_id, contest_id=contest.id).exists()):
             return contest
 
-        if not contest.is_visible and not user.has_perm('judge.see_private_contest') and (
-                not user.has_perm('judge.edit_own_contest') or
-                not self.check_organizer(contest, user)):
+        try:
+            contest.access_check(self.request.user)
+        except Contest.PrivateContest:
+            raise PrivateContestError(contest.name, contest.is_private, contest.is_organization_private,
+                                      contest.organizations.all())
+        except Contest.Inaccessible:
             raise Http404()
-
+        else:
+            return contest
+            
         if contest.is_private or contest.is_organization_private:
             private_contest_error = PrivateContestError(contest.name, contest.is_private,
                                                         contest.is_organization_private, contest.organizations.all())
@@ -297,7 +297,7 @@ class ContestClone(ContestMixin, PermissionRequiredMixin, TitleMixin, SingleObje
         contest.organizations.set(organizations)
         contest.private_contestants.set(private_contestants)
         contest.view_contest_scoreboard.set(view_contest_scoreboard)
-        contest.organizers.add(self.request.profile)
+        contest.authors.add(self.request.profile)
 
         for problem in contest_problems:
             problem.contest = contest
@@ -337,7 +337,7 @@ class ContestJoin(LoginRequiredMixin, ContestMixin, BaseDetailView):
     def join_contest(self, request, access_code=None):
         contest = self.object
 
-        if not contest.can_join and not self.is_organizer:
+        if not contest.can_join and not (self.is_editor or self.is_tester):
             return generic_message(request, _('Contest not ongoing'),
                                    _('"%s" is not currently ongoing.') % contest.name)
 
@@ -351,8 +351,7 @@ class ContestJoin(LoginRequiredMixin, ContestMixin, BaseDetailView):
                                    _('You have been declared persona non grata for this contest. '
                                      'You are permanently barred from joining this contest.'))
 
-        requires_access_code = (not (request.user.is_superuser or self.is_organizer) and
-                                contest.access_code and access_code != contest.access_code)
+        requires_access_code = (not self.can_edit and contest.access_code and access_code != contest.access_code)
         if contest.ended:
             if requires_access_code:
                 raise ContestAccessDenied()
@@ -371,22 +370,24 @@ class ContestJoin(LoginRequiredMixin, ContestMixin, BaseDetailView):
                 else:
                     break
         else:
+            SPECTATE = ContestParticipation.SPECTATE
+            LIVE = ContestParticipation.LIVE
             try:
                 participation = ContestParticipation.objects.get(
-                    contest=contest, user=profile, virtual=(-1 if self.is_organizer else 0),
+                    contest=contest, user=profile, virtual=(SPECTATE if self.is_editor or self.is_tester else LIVE),
                 )
             except ContestParticipation.DoesNotExist:
                 if requires_access_code:
                     raise ContestAccessDenied()
 
                 participation = ContestParticipation.objects.create(
-                    contest=contest, user=profile, virtual=(-1 if self.is_organizer else 0),
+                    contest=contest, user=profile, virtual=(SPECTATE if self.is_editor or self.is_tester else LIVE),
                     real_start=timezone.now(),
                 )
             else:
                 if participation.ended:
                     participation = ContestParticipation.objects.get_or_create(
-                        contest=contest, user=profile, virtual=-1,
+                        contest=contest, user=profile, virtual=SPECTATE,
                         defaults={'real_start': timezone.now()},
                     )[0]
 
@@ -449,7 +450,7 @@ class ContestCalendar(TitleMixin, ContestListMixin, TemplateView):
     def get_contest_data(self, start, end):
         end += timedelta(days=1)
         contests = self.get_queryset().filter(Q(start_time__gte=start, start_time__lt=end) |
-                                              Q(end_time__gte=start, end_time__lt=end)).defer('description')
+                                              Q(end_time__gte=start, end_time__lt=end))
         starts, ends, oneday = (defaultdict(list) for i in range(3))
         for contest in contests:
             start_date = timezone.localtime(contest.start_time).date()
@@ -530,7 +531,7 @@ class ContestStats(TitleMixin, ContestMixin, DetailView):
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
 
-        if not (self.object.ended or self.object.is_editable_by(self.request.user)):
+        if not (self.object.ended or self.can_edit):
             raise Http404()
 
         queryset = Submission.objects.filter(contest_object=self.object)
@@ -542,9 +543,10 @@ class ContestStats(TitleMixin, ContestMixin, DetailView):
             queryset.values('problem__code', 'result').annotate(count=Count('result'))
                     .values_list('problem__code', 'result', 'count'),
         )
-        labels, codes = zip(
-            *self.object.contest_problems.order_by('order').values_list('problem__name', 'problem__code'),
-        )
+        labels, codes = [], []
+        contest_problems = self.object.contest_problems.order_by('order').values_list('problem__name', 'problem__code')
+        if contest_problems:
+            labels, codes = zip(*contest_problems)
         num_problems = len(labels)
         status_counts = [[] for i in range(num_problems)]
         for problem_code, result, count in status_count_queryset:
@@ -630,10 +632,6 @@ def get_contest_ranking_list(request, contest, participation=None, ranking_list=
                              show_current_virtual=True, ranker=ranker):
     problems = list(contest.contest_problems.select_related('problem').defer('problem__description').order_by('order'))
 
-    if contest.hide_scoreboard and contest.is_in_contest(request.user):
-        return ([(_('???'), make_contest_ranking_profile(contest, request.profile.current_contest, problems))],
-                problems)
-
     users = ranker(ranking_list(contest, problems), key=attrgetter('points', 'cumtime'))
     
     if show_current_virtual:
@@ -651,7 +649,7 @@ def contest_ranking_ajax(request, contest, participation=None):
     if not exists:
         return HttpResponseBadRequest('Invalid contest', content_type='text/plain')
 
-    if not contest.can_see_scoreboard(request.user):
+    if not contest.can_see_full_scoreboard(request.user):
         raise Http404()
 
     users, problems = get_contest_ranking_list(request, contest, participation)
@@ -679,7 +677,7 @@ class ContestRankingBase(ContestMixin, TitleMixin, DetailView):
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
 
-        if not self.object.can_see_scoreboard(self.request.user):
+        if not self.object.can_see_own_scoreboard(self.request.user):
             raise Http404()
 
         users, problems = self.get_ranking_list()
@@ -697,6 +695,14 @@ class ContestRanking(ContestRankingBase):
         return _('%s Rankings') % self.object.name
 
     def get_ranking_list(self):
+        if not self.object.can_see_full_scoreboard(self.request.user):
+            queryset = self.object.users.filter(user=self.request.profile, virtual=ContestParticipation.LIVE)
+            return get_contest_ranking_list(
+                self.request, self.object,
+                ranking_list=partial(base_contest_ranking_list, queryset=queryset),
+                ranker=lambda users, key: ((_('???'), user) for user in users),
+            )
+
         return get_contest_ranking_list(self.request, self.object)
 
     def get_context_data(self, **kwargs):
@@ -714,6 +720,9 @@ class ContestParticipationList(LoginRequiredMixin, ContestRankingBase):
         return _("%s's participation in %s") % (self.profile.username, self.object.name)
 
     def get_ranking_list(self):
+        if not self.object.can_see_full_scoreboard(self.request.user) and self.profile != self.request.profile:
+            raise Http404()
+            
         queryset = self.object.users.filter(user=self.profile, virtual__gte=0).order_by('-virtual')
         live_link = format_html('<a href="{2}#!{1}">{0}</a>', _('Live'), self.profile.username,
                                 reverse('contest_ranking', args=[self.object.key]))
@@ -741,7 +750,7 @@ class ContestParticipationList(LoginRequiredMixin, ContestRankingBase):
 class ContestParticipationDisqualify(ContestMixin, SingleObjectMixin, View):
     def get_object(self, queryset=None):
         contest = super().get_object(queryset)
-        if not contest.is_editable_by(self.request.user):
+        if not self.can_edit:
             raise Http404()
         return contest
 
@@ -762,7 +771,7 @@ class ContestMossMixin(ContestMixin, PermissionRequiredMixin):
 
     def get_object(self, queryset=None):
         contest = super().get_object(queryset)
-        if settings.MOSS_API_KEY is None:
+        if settings.MOSS_API_KEY is None or not self.can_edit:
             raise Http404()
         if not contest.is_editable_by(self.request.user):
             raise Http404()
diff --git a/judge/views/problem.py b/judge/views/problem.py
index fbb2721..64f5f0d 100644
--- a/judge/views/problem.py
+++ b/judge/views/problem.py
@@ -438,7 +438,8 @@ class ProblemList(QueryStringSortMixin, TitleMixin, SolvedProblemMixin, ListView
         else:
             context['hot_problems'] = None
             context['point_start'], context['point_end'], context['point_values'] = 0, 0, {}
-            context['hide_contest_scoreboard'] = self.contest.hide_scoreboard
+            context['hide_contest_scoreboard'] = self.contest.scoreboard_visibility in \
+                (self.contest.SCOREBOARD_AFTER_CONTEST, self.contest.SCOREBOARD_AFTER_PARTICIPATION)
         return context
 
     def get_noui_slider_points(self):
diff --git a/judge/views/select2.py b/judge/views/select2.py
index cf8e249..0647f98 100644
--- a/judge/views/select2.py
+++ b/judge/views/select2.py
@@ -54,29 +54,14 @@ class OrganizationSelect2View(Select2View):
 
 class ProblemSelect2View(Select2View):
     def get_queryset(self):
-        queryset = Problem.objects.filter(Q(code__icontains=self.term) | Q(name__icontains=self.term))
-        if not self.request.user.has_perm('judge.see_private_problem'):
-            filter = Q(is_public=True)
-            if self.request.user.is_authenticated:
-                filter |= Q(authors=self.request.profile) | Q(curators=self.request.profile)
-            queryset = queryset.filter(filter).distinct()
-        return queryset.distinct()
+        return Problem.get_visible_problems(self.request.user) \
+                      .filter(Q(code__icontains=self.term) | Q(name__icontains=self.term))
 
 
 class ContestSelect2View(Select2View):
     def get_queryset(self):
-        queryset = Contest.objects.filter(Q(key__icontains=self.term) | Q(name__icontains=self.term))
-        if not self.request.user.has_perm('judge.see_private_contest'):
-            queryset = queryset.filter(is_visible=True)
-        if not self.request.user.has_perm('judge.edit_all_contest'):
-            q = Q(is_private=False, is_organization_private=False)
-            if self.request.user.is_authenticated:
-                q |= Q(is_organization_private=True,
-                       organizations__in=self.request.profile.organizations.all())
-                q |= Q(is_private=True, private_contestants=self.request.profile)
-                q |= Q(view_contest_scoreboard=self.request.profile)
-            queryset = queryset.filter(q)
-        return queryset
+        return Contest.get_visible_contests(self.request.user) \
+                      .filter(Q(key__icontains=self.term) | Q(name__icontains=self.term))
 
 
 class CommentSelect2View(Select2View):
@@ -119,8 +104,7 @@ class UserSearchSelect2View(BaseListView):
 class ContestUserSearchSelect2View(UserSearchSelect2View):
     def get_queryset(self):
         contest = get_object_or_404(Contest, key=self.kwargs['contest'])
-        if not contest.can_see_scoreboard(self.request.user) or \
-                contest.hide_scoreboard and contest.is_in_contest(self.request.user):
+        if not contest.is_accessible_by(self.request.user) or not contest.can_see_full_scoreboard(self.request.user):
             raise Http404()
 
         return Profile.objects.filter(contest_history__contest=contest,
diff --git a/judge/views/submission.py b/judge/views/submission.py
index 6c7d9e6..5f86ccf 100644
--- a/judge/views/submission.py
+++ b/judge/views/submission.py
@@ -43,7 +43,7 @@ from judge.utils.problems import get_result_data
 from judge.utils.problems import user_authored_ids
 from judge.utils.problems import user_completed_ids
 from judge.utils.problems import user_editable_ids
-from judge.utils.raw_sql import use_straight_join
+from judge.utils.raw_sql import join_sql_subquery, use_straight_join
 from judge.utils.views import DiggPaginatorMixin
 from judge.utils.views import TitleMixin
 
@@ -292,11 +292,9 @@ class SubmissionsListBase(DiggPaginatorMixin, TitleMixin, ListView):
                                                           queryset=ProblemTranslation.objects.filter(
                                                               language=self.request.LANGUAGE_CODE), to_attr='_trans'))
         if self.in_contest:
-            queryset = queryset.filter(
-                contest__participation__contest_id=self.contest.id)
-            if self.contest.hide_scoreboard and self.contest.is_in_contest(self.request.user):
-                queryset = queryset.filter(
-                    contest__participation__user=self.request.profile)
+            queryset = queryset.filter(contest_object=self.contest)
+            if not self.contest.can_see_full_scoreboard(self.request.user):
+                queryset = queryset.filter(user=self.request.profile)
         else:
             queryset = queryset.select_related(
                 'contest_object').defer('contest_object__description')
@@ -304,12 +302,18 @@ class SubmissionsListBase(DiggPaginatorMixin, TitleMixin, ListView):
             # This is not technically correct since contest organizers *should* see these, but
             # the join would be far too messy
             if not self.request.user.has_perm('judge.see_private_contest'):
-                queryset = queryset.exclude(
-                    contest_object_id__in=Contest.objects.filter(hide_scoreboard=True))
+                # Show submissions for any contest you can edit or visible scoreboard
+                contest_queryset = Contest.objects.filter(Q(authors=self.request.profile) |
+                                                          Q(curators=self.request.profile) |
+                                                          Q(scoreboard_visibility=Contest.SCOREBOARD_VISIBLE) |
+                                                          Q(end_time__lt=timezone.now())).distinct()
+                queryset = queryset.filter(Q(user=self.request.profile) |
+                                           Q(contest_object__in=contest_queryset) |
+                                           Q(contest_object__isnull=True))
 
         if self.selected_languages:
             queryset = queryset.filter(
-                language_id__in=Language.objects.filter(key__in=self.selected_languages))
+                language__in=Language.objects.filter(key__in=self.selected_languages))
         if self.selected_statuses:
             queryset = queryset.filter(result__in=self.selected_statuses)
 
@@ -318,14 +322,13 @@ class SubmissionsListBase(DiggPaginatorMixin, TitleMixin, ListView):
     def get_queryset(self):
         queryset = self._get_queryset()
         if not self.in_contest:
-            if not self.request.user.has_perm('judge.see_private_problem'):
-                queryset = queryset.filter(problem__is_public=True)
-            if not self.request.user.has_perm('judge.see_organization_problem'):
-                filter = Q(problem__is_organization_private=False)
-                if self.request.user.is_authenticated:
-                    filter |= Q(
-                        problem__organizations__in=self.request.profile.organizations.all())
-                queryset = queryset.filter(filter)
+            join_sql_subquery(
+                queryset,
+                subquery=str(Problem.get_visible_problems(self.request.user).distinct().only('id').query),
+                params=[],
+                join_fields=[('problem_id', 'id')],
+                alias='visible_problems',
+            )
         return queryset
 
     def get_my_submissions_page(self):
@@ -452,7 +455,7 @@ class ProblemSubmissionsBase(SubmissionsListBase):
                            reverse('problem_detail', args=[self.problem.code]))
 
     def access_check_contest(self, request):
-        if self.in_contest and not self.contest.can_see_scoreboard(request.user):
+        if self.in_contest and not self.contest.can_see_own_scoreboard(request.user):
             raise Http404()
 
     def access_check(self, request):
diff --git a/requirements.txt b/requirements.txt
index 735c38a..869deb8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -37,3 +37,4 @@ django-newsletter
 python-memcached
 netaddr
 redis
+lupa
\ No newline at end of file
diff --git a/resources/wpadmin/css/wpadmin.site.css b/resources/wpadmin/css/wpadmin.site.css
index af6b4c6..d60064c 100644
--- a/resources/wpadmin/css/wpadmin.site.css
+++ b/resources/wpadmin/css/wpadmin.site.css
@@ -50,7 +50,9 @@ select[id^=id_contest_problems] {
     width: 20em !important;
 }
 
-select#id_organizers.django-select2,
+select#id_authors.django-select2,
+select#id_curators.django-select2,
+select#id_testers.django-select2,
 select#id_organizations.django-select2,
 select#id_tags.django-select2 {
     width: 20em;
diff --git a/templates/admin/judge/contest/change_form.html b/templates/admin/judge/contest/change_form.html
index beb2122..7f540f6 100644
--- a/templates/admin/judge/contest/change_form.html
+++ b/templates/admin/judge/contest/change_form.html
@@ -13,7 +13,7 @@
 {% endblock extrahead %}
 
 {% block after_field_sets %}{{ block.super }}
-    {% if original and original.is_rated and perms.judge.contest_rating %}
+    {% if original and original.is_rated and original.ended and perms.judge.contest_rating %}
         <a style="display: none" title="{% trans "Rate" %}" href="{% url 'admin:judge_contest_rate' original.pk %}"
            class="button rerate-link">
             <i class="fa fa-lg fa-signal"></i>
diff --git a/templates/contest/contest-tabs.html b/templates/contest/contest-tabs.html
index 6743433..d063a24 100644
--- a/templates/contest/contest-tabs.html
+++ b/templates/contest/contest-tabs.html
@@ -2,21 +2,21 @@
 
 {% block tabs %}
     {{ make_tab('detail', 'fa-info-circle', url('contest_view', contest.key), _('Info')) }}
-    {% if contest.ended or contest.is_editable_by(request.user) %}
+    {% if contest.ended or can_edit %}
         {{ make_tab('stats', 'fa-pie-chart', url('contest_stats', contest.key), _('Statistics')) }}
     {% endif %}
 
     {% if contest.start_time <= now or perms.judge.see_private_contest %}
-        {% if contest.show_scoreboard or contest.can_see_scoreboard(request.user) %}
+        {% if contest.can_see_own_scoreboard(request.user) %}
             {{ make_tab('ranking', 'fa-bar-chart', url('contest_ranking', contest.key), _('Rankings')) }}
+            {% if request.user.is_authenticated %}
+                {{ make_tab('participation', 'fa-users', url('contest_participation_own', contest.key), _('Participation')) }}
+            {% endif %}
         {% else %}
             {{ make_tab('ranking', 'fa-bar-chart', None, _('Hidden Rankings')) }}
         {% endif %}
-        {% if contest.show_scoreboard and request.user.is_authenticated %}
-            {{ make_tab('participation', 'fa-users', url('contest_participation_own', contest.key), _('Participation')) }}
-        {% endif %}
     {% endif %}
-    {% if contest.is_editable_by(request.user) %}
+    {% if can_edit %}
         {% if perms.judge.moss_contest and has_moss_api_key %}
             {{ make_tab('moss', 'fa-gavel', url('contest_moss', contest.key), _('MOSS')) }}
         {% endif %}
@@ -27,17 +27,18 @@
     {% endif %}
 
     {% if request.user.is_authenticated %}
-        {% if contest.can_join or participating or is_organizer %}
+        {% if contest.can_join or is_editor or is_tester %}
+            {% set in_contest = contest.is_in_contest(request.user) %}
             {% if contest.ended %}
+                {# Allow users to leave the virtual contest #}
                 {% if in_contest %}
-                    {# They're in the contest because they're participating virtually #}
                     <form action="{{ url('contest_leave', contest.key) }}" method="post"
                           class="contest-join-pseudotab unselectable button full">
                         {% csrf_token %}
                         <input type="submit" class="leaving-forever" value="{{ _('Leave contest') }}">
                     </form>
                 {% else %}
-                    {# They're in the contest because they're participating virtually #}
+                    {# Allow users to virtual join #}
                     <form action="{{ url('contest_join', contest.key) }}" method="post"
                           class="contest-join-pseudotab unselectable button full">
                         {% csrf_token %}
@@ -45,35 +46,30 @@
                     </form>
                 {% endif %}
             {% else %}
+                {# Allow users to leave the contest #}
                 {% if in_contest %}
-                    {# Allow people with ended participations to continue spectating #}
                     <form action="{{ url('contest_leave', contest.key) }}" method="post"
                           class="contest-join-pseudotab unselectable button full">
                         {% csrf_token %}
                         <input type="submit" value="
-                            {%- if participating and participation.ended or request.profile in contest.organizers.all() %}
+                            {%- if request.participation.spectate %}
                                 {{- _('Stop spectating') -}}
                             {% else %}
                                 {{- _('Leave contest') -}}
                             {% endif %}">
                     </form>
-                {% elif participating and participation.ended or is_organizer %}
+                {% elif is_editor or is_tester or live_participation.ended %}
                     <form action="{{ url('contest_join', contest.key) }}" method="post"
                           class="contest-join-pseudotab unselectable button full">
                         {% csrf_token %}
                         <input type="submit" value="{{ _('Spectate contest') }}">
                     </form>
-                {% elif participating %}
-                    <form action="{{ url('contest_join', contest.key) }}" method="post"
-                          class="contest-join-pseudotab unselectable button full">
-                        {% csrf_token %}
-                        <input type="submit" value="{{ _('Join contest') }}">
-                    </form>
                 {% else %}
                     <form action="{{ url('contest_join', contest.key) }}" method="post"
                           class="contest-join-pseudotab unselectable button full">
                         {% csrf_token %}
-                        <input type="submit" class="first-join" value="{{ _('Join contest') }}">
+                        <input type="submit" {% if not has_joined %}class="first-join"{% endif %}
+                               value="{{ _('Join contest') }}">
                     </form>
                 {% endif %}
             {% endif %}
diff --git a/templates/contest/contest.html b/templates/contest/contest.html
index 9d15cc6..a65d881 100644
--- a/templates/contest/contest.html
+++ b/templates/contest/contest.html
@@ -28,11 +28,11 @@
     <div id="banner">
         <a href="https://www.timeanddate.com/worldclock/fixedtime.html?msg={{ contest.name|urlquote('') }}&amp;iso=
                 {{- contest.start_time|utc|date('Y-m-d\TH:i:s') }}" class="date">
-            {%- if participating and participation.virtual and not participation.ended -%}
-                {% if participation.spectate %}
+            {%- if contest.is_in_contest(request.user) and not request.participation.live -%}
+                {% if request.participation.spectate %}
                     {{- _('Spectating, contest ends in %(countdown)s.', countdown=contest.time_before_end|as_countdown) -}}
-                {% elif participation.end_time %}
-                    {{- _('Participating virtually, %(countdown)s remaining.', countdown=participation.time_remaining|as_countdown) -}}
+                {% elif request.participation.end_time %}
+                    {{- _('Participating virtually, %(countdown)s remaining.', countdown=request.participation.time_remaining|as_countdown) -}}    
                 {% else %}
                     {{- _('Participating virtually.') -}}
                 {% endif %}
@@ -42,11 +42,11 @@
                 {% elif contest.end_time < now %}
                     {{- _('Contest is over.') -}}
                 {% else %}
-                    {%- if participating -%}
-                        {% if participation.ended %}
+                    {%- if has_joined -%}
+                        {% if live_participation.ended %}
                             {{- _('Your time is up! Contest ends in %(countdown)s.', countdown=contest.time_before_end|as_countdown) -}}
                         {% else %}
-                            {{- _('You have %(countdown)s remaining.', countdown=participation.time_remaining|as_countdown) -}}
+                            {{- _('You have %(countdown)s remaining.', countdown=live_participation.time_remaining|as_countdown) -}}
                         {% endif %}
                     {%- else -%}
                         {{ _('Contest ends in %(countdown)s.', countdown=contest.time_before_end|as_countdown) }}
@@ -73,7 +73,7 @@
         {% endcache %}
     </div>
 
-    {% if contest.ended or request.user.is_superuser or is_organizer %}
+    {% if contest.ended or request.user.is_superuser or is_editor or is_tester %}
         <hr>
         <div class="contest-problems">
             <h2 style="margin-bottom: 0.2em"><i class="fa fa-fw fa-question-circle"></i>{{ _('Problems') }} </h2>
diff --git a/templates/contest/list.html b/templates/contest/list.html
index f10b067..9cfbc5c 100644
--- a/templates/contest/list.html
+++ b/templates/contest/list.html
@@ -185,7 +185,7 @@
 {% endmacro %}
 
 {% macro user_count(contest, user) %}
-    {% if contest.show_scoreboard or contest.can_see_scoreboard(user) %}
+    {% if contest.can_see_own_scoreboard(user) %}
         <a href="{{ url('contest_ranking', contest.key) }}">{{ contest.user_count }}</a>
     {% else %}
         {{ contest.user_count }}
@@ -195,7 +195,7 @@
 {% macro contest_join(contest, request) %}
     {% if not request.in_contest %}
         <td>
-            {% if request.profile in contest.organizers.all() %}
+            {% if request.profile in contest.authors.all() or request.profile in contest.curators.all() or request.profile in contest.testers.all() %}
                 <form action="{{ url('contest_join', contest.key) }}" method="post">
                     {% csrf_token %}
                     <input type="submit" class="unselectable button full participate-button"
diff --git a/templates/contest/ranking-table.html b/templates/contest/ranking-table.html
index c18e2b2..d90c281 100644
--- a/templates/contest/ranking-table.html
+++ b/templates/contest/ranking-table.html
@@ -32,7 +32,7 @@
 {% endblock %}
 
 {% block user_data %}
-    {% if is_organizer %}
+    {% if can_edit %}
         <span class="contest-participation-operation">
             <form action="{{ url('contest_participation_disqualify', contest.key) }}" method="post">
                 {% csrf_token %}
@@ -56,7 +56,7 @@
 {% block before_point_head %}
     {% for problem in problems %}
         <th class="points header problem-score-col"><a href="{{ url('contest_ranked_submissions', contest.key, problem.problem.code) }}">
-            {{- loop.index }}
+            {{- contest.get_label_for_problem(loop.index0) }}
             <div class="point-denominator">{{ problem.points }}</div>
         </a></th>
     {% endfor %}
diff --git a/templates/contest/ranking.html b/templates/contest/ranking.html
index a8f2ace..63b0538 100644
--- a/templates/contest/ranking.html
+++ b/templates/contest/ranking.html
@@ -179,7 +179,7 @@
 {% endblock %}
 
 {% block users_js_media %}
-    {% if is_organizer %}
+    {% if can_edit %}
         <script type="text/javascript">
             $(function () {
                 $('a.disqualify-participation').click(function (e) {
@@ -349,7 +349,7 @@
 {% block users_table %}
     <div style="margin-bottom: 0.5em">
         {% if tab == 'participation' %}
-            {% if contest.start_time <= now or perms.judge.see_private_contest %}
+            {% if contest.can_see_full_scoreboard(request.user) %}
                 <input id="search-contest" type="text" placeholder="{{ _('View user participation') }}">
             {% endif %}
         {% endif %}