diff --git a/account/urls/oj.py b/account/urls/oj.py
index 0af54a5..c1915f4 100644
--- a/account/urls/oj.py
+++ b/account/urls/oj.py
@@ -4,7 +4,8 @@ from ..views.oj import (ApplyResetPasswordAPI, ResetPasswordAPI,
                         UserChangePasswordAPI, UserRegisterAPI, UserChangeEmailAPI,
                         UserLoginAPI, UserLogoutAPI, UsernameOrEmailCheck,
                         AvatarUploadAPI, TwoFactorAuthAPI, UserProfileAPI,
-                        UserRankAPI, CheckTFARequiredAPI, SessionManagementAPI)
+                        UserRankAPI, CheckTFARequiredAPI, SessionManagementAPI,
+                        ProfileProblemDisplayIDRefreshAPI)
 
 from utils.captcha.views import CaptchaAPIView
 
@@ -19,6 +20,7 @@ urlpatterns = [
     url(r"^captcha/?$", CaptchaAPIView.as_view(), name="show_captcha"),
     url(r"^check_username_or_email", UsernameOrEmailCheck.as_view(), name="check_username_or_email"),
     url(r"^profile/?$", UserProfileAPI.as_view(), name="user_profile_api"),
+    url(r"^profile/fresh_display_id", ProfileProblemDisplayIDRefreshAPI.as_view(), name="display_id_fresh"),
     url(r"^upload_avatar/?$", AvatarUploadAPI.as_view(), name="avatar_upload_api"),
     url(r"^tfa_required/?$", CheckTFARequiredAPI.as_view(), name="tfa_required_check"),
     url(r"^two_factor_auth/?$", TwoFactorAuthAPI.as_view(), name="two_factor_auth_api"),
diff --git a/account/views/admin.py b/account/views/admin.py
index 6ae3baa..9d1359f 100644
--- a/account/views/admin.py
+++ b/account/views/admin.py
@@ -1,5 +1,6 @@
 from django.db.models import Q
 
+from submission.models import Submission
 from utils.api import APIView, validate_serializer
 from utils.shortcuts import rand_str
 
@@ -25,6 +26,7 @@ class UserAdminAPI(APIView):
         if User.objects.filter(email=data["email"].lower()).exclude(id=user.id).exists():
             return self.error("Email already exists")
 
+        pre_username = user.username
         user.username = data["username"]
         user.email = data["email"]
         user.admin_type = data["admin_type"]
@@ -58,6 +60,8 @@ class UserAdminAPI(APIView):
         user.two_factor_auth = data["two_factor_auth"]
 
         user.save()
+        if pre_username != user.username:
+            Submission.objects.filter(username=pre_username).update(username=user.username)
         return self.success(UserSerializer(user).data)
 
     @super_admin_required
diff --git a/account/views/oj.py b/account/views/oj.py
index 76d363f..50aa9db 100644
--- a/account/views/oj.py
+++ b/account/views/oj.py
@@ -11,6 +11,7 @@ from django.utils.timezone import now
 from django.views.decorators.csrf import ensure_csrf_cookie
 from otpauth import OtpAuth
 
+from problem.models import Problem
 from utils.constants import ContestRuleType
 from options.options import SysOptions
 from utils.api import APIView, validate_serializer
@@ -379,3 +380,21 @@ class UserRankAPI(APIView):
         else:
             profiles = profiles.filter(total_score__gt=0).order_by("-total_score")
         return self.success(self.paginate_data(request, profiles, RankInfoSerializer))
+
+
+class ProfileProblemDisplayIDRefreshAPI(APIView):
+    @login_required
+    def get(self, request):
+        profile = request.user.userprofile
+        acm_problems = profile.acm_problems_status["problems"]
+        oi_problems = profile.oi_problems_status["problems"]
+        ids = list(acm_problems.keys()) + list(oi_problems.keys())
+        display_ids = Problem.objects.filter(id__in=ids).values_list("_id", flat=True)
+        id_map = dict(zip(ids, display_ids))
+        print(id_map)
+        for k, v in acm_problems.items():
+            v["_id"] = id_map[k]
+        for k, v in oi_problems.items():
+            v["_id"] = id_map[k]
+        profile.save(update_fields=["acm_problems_status", "oi_problems_status"])
+        return self.success()
diff --git a/contest/views/oj.py b/contest/views/oj.py
index d50e0e9..612ebd4 100644
--- a/contest/views/oj.py
+++ b/contest/views/oj.py
@@ -16,7 +16,7 @@ class ContestAnnouncementListAPI(APIView):
     def get(self, request):
         contest_id = request.GET.get("contest_id")
         if not contest_id:
-            return self.error("Invalid parameter")
+            return self.error("Invalid parameter, contest_id is required")
         data = ContestAnnouncement.objects.select_related("created_by").filter(contest_id=contest_id, visible=True)
         max_id = request.GET.get("max_id")
         if max_id:
@@ -28,7 +28,7 @@ class ContestAPI(APIView):
     def get(self, request):
         id = request.GET.get("id")
         if not id:
-            return self.error("Invalid parameter")
+            return self.error("Invalid parameter, id is required")
         try:
             contest = Contest.objects.get(id=id)
             return self.success(ContestSerializer(contest).data)