diff --git a/account/api.py b/account/api.py
index 00f6e58..91ef8a1 100644
--- a/account/api.py
+++ b/account/api.py
@@ -6,6 +6,7 @@ from ninja.pagination import paginate
 from ninja.errors import HttpError
 from .schemas import (
     BatchUsersIn,
+    ClassStudentEntry,
     LeaderboardEntry,
     UserListSchema,
     UserRegistrationSchema,
@@ -96,7 +97,7 @@ def batch_create(request, payload: BatchUsersIn):
     # 批量创建用户
     for username in usernames:
         password = generate_password()
-        user = User(username=username)
+        user = User(username=username, classname=payload.classname)
         user.set_password(password)
         users_to_create.append(user)
 
@@ -135,3 +136,28 @@ def leaderboard(request):
         LeaderboardEntry(rank=i + 1, username=p.user.username, total_score=p.total_score)
         for i, p in enumerate(profiles)
     ]
+
+
+@router.get("/classes", response=List[str])
+def list_classes(request):
+    """返回所有不重复的非空班级名列表，按字典序升序"""
+    return (
+        User.objects.filter(classname__gt="")
+        .values_list("classname", flat=True)
+        .distinct()
+        .order_by("classname")
+    )
+
+
+@router.get("/names", response=List[ClassStudentEntry])
+def list_names_by_class(request, classname: str):
+    """返回指定班级的学生姓名和用户名列表"""
+    prefix = "web" + classname
+    users = User.objects.filter(
+        classname=classname,
+        username__startswith=prefix,
+    ).order_by("username")
+    return [
+        ClassStudentEntry(name=u.username[len(prefix):], username=u.username)
+        for u in users
+    ]
diff --git a/account/migrations/0003_user_classname.py b/account/migrations/0003_user_classname.py
new file mode 100644
index 0000000..cb78f24
--- /dev/null
+++ b/account/migrations/0003_user_classname.py
@@ -0,0 +1,18 @@
+# Generated by Django 6.0.1 on 2026-03-18 02:33
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('account', '0002_alter_profile_total_score'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='user',
+            name='classname',
+            field=models.CharField(blank=True, default='', max_length=50, verbose_name='班级'),
+        ),
+    ]
diff --git a/account/models.py b/account/models.py
index 4ea60a0..8e2a344 100644
--- a/account/models.py
+++ b/account/models.py
@@ -27,6 +27,12 @@ class User(AbstractUser):
         blank=True,
         verbose_name="明文密码",
     )
+    classname = models.CharField(
+        max_length=50,
+        blank=True,
+        default="",
+        verbose_name="班级",
+    )
 
     def save(self, *args, **kwargs):
         if self.username:
diff --git a/account/schemas.py b/account/schemas.py
index b082c02..a687b6f 100644
--- a/account/schemas.py
+++ b/account/schemas.py
@@ -52,3 +52,8 @@ class LeaderboardEntry(Schema):
     rank: int
     username: str
     total_score: float
+
+
+class ClassStudentEntry(Schema):
+    name: str
+    username: str
diff --git a/api/settings.py b/api/settings.py
index 8966b0f..8353eaa 100644
--- a/api/settings.py
+++ b/api/settings.py
@@ -205,4 +205,4 @@ MEDIA_ROOT = BASE_DIR / "media"
 # LLM Configuration
 LLM_API_KEY = os.environ.get("LLM_API_KEY", "")
 LLM_BASE_URL = os.environ.get("LLM_BASE_URL", "https://api.deepseek.com")
-LLM_MODEL = os.environ.get("LLM_MODEL", "deepseek-chat")
+LLM_MODEL = os.environ.get("LLM_MODEL", "deepseek-reasoner")
diff --git a/submission/api.py b/submission/api.py
index 402b181..5306d0a 100644
--- a/submission/api.py
+++ b/submission/api.py
@@ -5,7 +5,7 @@ from ninja.errors import HttpError
 from ninja.pagination import paginate
 from django.shortcuts import get_object_or_404
 from django.contrib.auth.decorators import login_required
-from django.db.models import OuterRef, Subquery, IntegerField
+from django.db.models import Count, OuterRef, Q, Subquery, IntegerField
 
 
 from .schemas import (
@@ -40,6 +40,11 @@ def create_submission(request, payload: SubmissionIn):
         )
         conversation.is_active = False
         conversation.save(update_fields=["is_active"])
+    # 如果用户之前已参与排名，自动转移提名到新提交
+    had_nomination = Submission.objects.filter(
+        user=request.user, task=task, nominated=True
+    ).update(nominated=False) > 0
+
     Submission.objects.create(
         user=request.user,
         task=task,
@@ -47,6 +52,7 @@ def create_submission(request, payload: SubmissionIn):
         css=payload.css,
         js=payload.js,
         conversation=conversation,
+        nominated=had_nomination,
     )
 
 
@@ -68,8 +74,34 @@ def list_submissions(request, filters: SubmissionFilter = Query(...)):
         submissions = submissions.filter(task__task_type=filters.task_type)
     if filters.username:
         submissions = submissions.filter(user__username__icontains=filters.username)
+    if filters.user_id:
+        submissions = submissions.filter(user_id=filters.user_id)
     if filters.flag:
-        submissions = submissions.filter(flag=filters.flag)
+        if filters.flag == "any":
+            submissions = submissions.filter(flag__isnull=False)
+        else:
+            submissions = submissions.filter(flag=filters.flag)
+
+    if filters.nominated is not None:
+        submissions = submissions.filter(nominated=filters.nominated)
+    if filters.score_lt_threshold is not None:
+        submissions = submissions.filter(score__lt=filters.score_lt_threshold)
+    else:
+        if filters.score_min is not None:
+            submissions = submissions.filter(score__gte=filters.score_min)
+        if filters.score_max_exclusive is not None:
+            submissions = submissions.filter(score__lt=filters.score_max_exclusive)
+    if filters.ordering in ("-score", "score", "-created"):
+        submissions = submissions.order_by(filters.ordering)
+
+    if filters.grouped:
+        # 分组模式：每个 (user, task) 只保留最新一条
+        latest_per_group = (
+            Submission.objects.filter(user=OuterRef("user"), task=OuterRef("task"))
+            .order_by("-created")
+            .values("pk")[:1]
+        )
+        submissions = submissions.filter(pk=Subquery(latest_per_group))
 
     user_rating_subquery = Subquery(
         Rating.objects.filter(user=request.user, submission=OuterRef("pk")).values(
@@ -79,6 +111,15 @@ def list_submissions(request, filters: SubmissionFilter = Query(...)):
     )
     submissions = submissions.annotate(my_score=user_rating_subquery)
 
+    # 同一用户同一任务的提交次数
+    submit_count_subquery = Subquery(
+        Submission.objects.filter(
+            user=OuterRef("user"), task=OuterRef("task")
+        ).values("user", "task").annotate(c=Count("id")).values("c")[:1],
+        output_field=IntegerField(),
+    )
+    submissions = submissions.annotate(submit_count=submit_count_subquery)
+
     return submissions
 
 
@@ -104,6 +145,50 @@ def my_scores(request):
 
 
 
+@router.get("/by-user-task", response=List[SubmissionOut])
+@login_required
+def list_by_user_task(request, user_id: int, task_id: int):
+    """
+    获取某用户某任务的所有提交（不分页）
+    """
+    user_rating_subquery = Subquery(
+        Rating.objects.filter(user=request.user, submission=OuterRef("pk")).values(
+            "score"
+        )[:1],
+        output_field=IntegerField(),
+    )
+    return (
+        Submission.objects.filter(user_id=user_id, task_id=task_id)
+        .select_related("task", "user")
+        .defer("html", "css", "js")
+        .annotate(my_score=user_rating_subquery)
+        .order_by("-created")
+    )
+
+
+@router.delete("/flags")
+@login_required
+def clear_all_flags(request):
+    """
+    清除所有提交的标记（仅管理员和超级管理员可操作）
+    """
+    if request.user.role not in (RoleChoices.SUPER, RoleChoices.ADMIN):
+        raise HttpError(403, "没有权限")
+
+    count = Submission.objects.filter(flag__isnull=False).update(flag=None)
+    return {"cleared": count}
+
+
+@router.delete("/{submission_id}")
+@login_required
+def delete_submission(request, submission_id: UUID):
+    submission = get_object_or_404(Submission, id=submission_id)
+    if submission.user != request.user:
+        raise HttpError(403, "只能删除自己的提交")
+    submission.delete()
+    return {"message": "删除成功"}
+
+
 @router.get("/{submission_id}", response=SubmissionOut)
 @login_required
 def get_submission(request, submission_id: UUID):
@@ -161,3 +246,27 @@ def update_flag(request, submission_id: UUID, payload: FlagIn):
     submission.flag = payload.flag
     submission.save(update_fields=["flag"])
     return {"flag": submission.flag}
+
+
+@router.put("/{submission_id}/nominate")
+@login_required
+def nominate_submission(request, submission_id: UUID):
+    """
+    学生将某条提交标记为"参与排名"。
+    同一用户同一题目只能有一条参与排名，旧的自动取消。
+    """
+    submission = get_object_or_404(Submission, id=submission_id)
+
+    if submission.user != request.user:
+        raise HttpError(403, "只能提名自己的提交")
+
+    Submission.objects.filter(
+        user=request.user,
+        task=submission.task,
+        nominated=True,
+    ).exclude(pk=submission.pk).update(nominated=False)
+
+    submission.nominated = True
+    submission.save(update_fields=["nominated"])
+
+    return {"nominated": True}
diff --git a/submission/management/__init__.py b/submission/management/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/submission/migrations/0006_add_raw_score_nominated.py b/submission/migrations/0006_add_raw_score_nominated.py
new file mode 100644
index 0000000..ee31ebe
--- /dev/null
+++ b/submission/migrations/0006_add_raw_score_nominated.py
@@ -0,0 +1,23 @@
+# Generated by Django 6.0.1 on 2026-03-16 11:21
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('submission', '0005_add_flag_index'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='submission',
+            name='nominated',
+            field=models.BooleanField(db_index=True, default=False, verbose_name='参与排名'),
+        ),
+        migrations.AddField(
+            model_name='submission',
+            name='raw_score',
+            field=models.FloatField(default=0.0, verbose_name='原始加权分'),
+        ),
+    ]
diff --git a/submission/models.py b/submission/models.py
index 1413c95..6fd1a27 100644
--- a/submission/models.py
+++ b/submission/models.py
@@ -1,5 +1,6 @@
 import uuid
 from django.db import models
+from django.db.models import Avg
 from django_extensions.db.models import TimeStampedModel
 from django.core.exceptions import ValidationError
 from django.utils import timezone
@@ -47,6 +48,8 @@ class Submission(TimeStampedModel):
         db_index=True,
         verbose_name="标记",
     )
+    raw_score = models.FloatField(default=0.0, verbose_name="原始加权分")
+    nominated = models.BooleanField(default=False, db_index=True, verbose_name="参与排名")
 
     class Meta:
         ordering = ("-created",)
@@ -61,30 +64,32 @@ class Submission(TimeStampedModel):
         return self.task.task_type
 
     def update_score(self):
-        """
-        更新当前Submission的分数
-        """
         ratings = list(self.ratings.select_related("user").all())
+        n = len(ratings)
 
-        super_score = 0.0
-        admin_score = 0.0
-        normal_score = 0.0
-
-        for rating in ratings:
-            if rating.user.role == RoleChoices.SUPER:
-                super_score += rating.score
-            elif rating.user.role == RoleChoices.ADMIN:
-                admin_score += rating.score
-            else:
-                normal_score += rating.score
-
-        if ratings:
-            total_score = super_score * 0.5 + admin_score * 0.3 + normal_score * 0.2
-            self.score = total_score / len(ratings)
-        else:
+        if n == 0:
+            self.raw_score = 0.0
             self.score = 0.0
+            self.save(update_fields=["raw_score", "score"])
+            return
 
-        self.save(update_fields=["score"])
+        weighted_sum = sum(
+            r.score * (0.5 if r.user.role == RoleChoices.SUPER
+                       else 0.3 if r.user.role == RoleChoices.ADMIN
+                       else 0.2)
+            for r in ratings
+        )
+        self.raw_score = weighted_sum / n
+
+        C = 3
+        global_mean = (
+            Submission.objects.filter(raw_score__gt=0)
+            .exclude(pk=self.pk)
+            .aggregate(Avg("raw_score"))["raw_score__avg"]
+        ) or self.raw_score
+
+        self.score = (C * global_mean + n * self.raw_score) / (C + n)
+        self.save(update_fields=["raw_score", "score"])
 
     def save(self, *args, **kwargs):
         super().save(*args, **kwargs)
diff --git a/submission/schemas.py b/submission/schemas.py
index 822667e..1f4941d 100644
--- a/submission/schemas.py
+++ b/submission/schemas.py
@@ -26,6 +26,8 @@ class SubmissionOut(Schema):
     js: Optional[str] = None
     conversation_id: Optional[UUID] = None
     flag: Optional[str] = None
+    nominated: bool = False
+    submit_count: int = 0
     created: str
     modified: str
 
@@ -57,6 +59,10 @@ class SubmissionOut(Schema):
     def resolve_my_score(obj):
         return getattr(obj, "my_score", None) or 0
 
+    @staticmethod
+    def resolve_submit_count(obj):
+        return getattr(obj, "submit_count", None) or 0
+
     @staticmethod
     def resolve_created(obj):
         return obj.created.isoformat()
@@ -82,6 +88,7 @@ class SubmissionOut(Schema):
             "js": submission.js,
             "conversation_id": submission.conversation_id,
             "flag": submission.flag,
+            "nominated": submission.nominated,
             "created": submission.created.isoformat(),
             "modified": submission.modified.isoformat(),
         }
@@ -100,7 +107,14 @@ class SubmissionFilter(Schema):
     task_id: Optional[int] = None
     task_type: Optional[Literal["tutorial", "challenge"]] = None
     username: Optional[str] = None
-    flag: Optional[Literal["red", "blue", "green", "yellow"]] = None
+    user_id: Optional[int] = None
+    flag: Optional[Literal["red", "blue", "green", "yellow", "any"]] = None
+    score_min: Optional[float] = None
+    score_max_exclusive: Optional[float] = None
+    score_lt_threshold: Optional[float] = None
+    nominated: Optional[bool] = None
+    ordering: Optional[str] = None
+    grouped: Optional[bool] = True
 
 
 class FlagIn(Schema):