fix(be): fix contest leaderboard ranking malfunction by zero1177 · Pull Request #3419 · skkuding/codedang

zero1177 · 2026-02-10T15:08:27Z

Description

Contest 리더보드 순위 오류 수정

변경사항

solvedProblemCount(1순위)가 동일할 경우, penalty(2순위)가 적은 user가 상위 rank에 오도록 정렬 로직 추가
lastAcceptedTime 기준으로 정답 제출이 더 빠른 유저가 상위 등수이도록 3순위 정렬 로직 추가

테스트

contest 7 기준
contestProblem 문제는 problemId 5,6,7,8 총 4개 (점수 각각 50, 60, 70, 80)

user02~user08 까지 7명의 user 대회 기록 생성 (seed.ts)

solvedProblemCount가 동일할 경우, penalty가 적은 user가 상위 rank
solvedProblemCount, penalty까지 모두 동일할 경우 lastAcceptedTime이 작은 (정답 제출이 더 빠른) 유저가 상위 rank

const testData = [
    {
      // user02 (2등) 3솔
      scores: [50, 60, 70, 0], //180점
      penalties: [30, 30, 40, 0], //100
      finishTime: [
        new Date('2026-03-01T09:20:00Z'),
        new Date('2026-03-01T09:35:00Z'),
        new Date('2026-03-01T10:20:00Z'),
        null
      ]
    },
    {
      // user03 (1등) 4솔
      scores: [50, 60, 70, 80], //260
      penalties: [15, 100, 55, 200], //370
      finishTime: [
        new Date('2026-03-01T09:15:00Z'),
        new Date('2026-03-01T10:15:00Z'),
        new Date('2026-03-01T10:00:00Z'),
        new Date('2026-03-01T10:50:00Z')
      ]
    },
    {
      // user04 (3등) 3솔
      scores: [0, 60, 70, 80], //210
      penalties: [0, 150, 20, 300], //470
      finishTime: [
        null,
        new Date('2026-03-01T10:30:00Z'),
        new Date('2026-03-01T09:30:00Z'),
        new Date('2026-03-01T11:30:00Z')
      ]
    },
    {
      // user05 (6등) 2솔
      scores: [0, 0, 70, 80], //150
      penalties: [0, 0, 150, 100], //250
      finishTime: [
        null,
        null,
        new Date('2026-03-01T10:40:00Z'),
        new Date('2026-03-01T10:10:00Z')
      ]
    },
    {
      //user06 (7등) 1솔
      scores: [0, 0, 70, 0], //70
      penalties: [0, 0, 150, 0], //150
      finishTime: [null, null, new Date('2026-03-01T10:30:00Z'), null]
    },
    {
      //user07 (4등) 2솔 - user08보다 lastAcceptedTime이 빠름
      scores: [50, 60, 0, 0], //110
      penalties: [20, 35, 0, 0], //55
      finishTime: [
        new Date('2026-03-01T09:20:00Z'),
        new Date('2026-03-01T09:40:00Z'), // lastAccepted = 09:40
        null,
        null
      ]
    },
    {
      //user08 (5등) 2솔 - user07보다 lastAcceptedTime이 늦음
      scores: [0, 60, 70, 0], //130
      penalties: [0, 35, 20, 0], //55
      finishTime: [
        null,
        new Date('2026-03-01T09:55:00Z'),
        new Date('2026-03-01T10:05:00Z'), // lastAccepted = 10:05
        null
      ]
    }

Before submitting the PR, please make sure you do the following

Read the Contributing Guidelines
Read the Contributing Guidelines and follow the Commit Convention
Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
Ideally, include relevant tests that fail without this PR but pass with it.

skkuding-bot · 2026-02-10T15:14:38Z

✅ Syncing Preview App Succeeded

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hjkim24 · 2026-03-25T11:03:12Z

/gemini review

gemini-code-assist

Code Review

This pull request refactors the contest leaderboard calculation logic in ContestService, introducing custom sorting and ranking based on solved problems and penalties, and adds new seeding data for contestId7 to test these changes. The review highlights a performance regression in ContestService due to sequential database queries that should be parallelized using Promise.all. Additionally, the new ranking logic in ContestService does not correctly handle ties, and a related comment is misleading. In prisma/seed.ts, the newly created contest7Records are not included in the function's return value, and there's a typo in a comment describing the number of solved problems for a test user.

…& penalty and add seed data

hjkim24 · 2026-04-26T07:20:26Z

/gemini review

gemini-code-assist

Code Review

This pull request refactors the leaderboard calculation logic in ContestService, moving sorting and ranking from the database query to application memory. It introduces manual calculation of scores, penalties, and solved problem counts, and implements a ranking algorithm to handle ties. Additionally, seed data for testing these changes was added. The review feedback suggests enhancing the sorting and ranking logic by incorporating totalScore and lastAcceptedTime as tie-breakers to ensure fairness and accuracy.

…2-modify-contest-statistics-leaderboard

zero1177 · 2026-04-27T13:02:32Z

/gemini review

gemini-code-assist

Code Review

This pull request refactors the contest leaderboard logic to calculate rankings based on the number of solved problems, total penalty, and the last accepted time. It also introduces new seed data for testing these ranking criteria. Feedback highlights a logic mismatch between the sorting and ranking assignment steps regarding totalScore, potential inconsistencies with other statistics methods in the service, and missing finishTime data in the new test seeds.

Copilot

Pull request overview

This PR fixes incorrect contest leaderboard ranking by changing how leaderboard entries are aggregated and ranked (with additional seed data to reproduce/test the issue).

Changes:

Reworked /contest/:id/leaderboard ranking to derive solved/penalty from per-problem records and sort accordingly.
Added seed data for contest 7 to reproduce leaderboard ranking scenarios.
Updated the Bruno collection request to call contest 7’s leaderboard.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 8 comments.

File	Description
collection/client/Contest/Get Leaderboard/Succeed.bru	Points the sample leaderboard request to contest id 7 for testing.
apps/backend/prisma/seed.ts	Adds contest 7 seed records intended for leaderboard ranking validation.
apps/backend/apps/client/src/contest/contest.service.ts	Recomputes leaderboard totals and implements in-memory sorting + rank assignment.

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Co-authored-by: Copilot <copilot@github.com>

zero1177 · 2026-04-30T10:33:25Z

/gemini review

gemini-code-assist

Code Review

This pull request updates the contest leaderboard logic to include lastAcceptedTime as a tie-breaking criterion and transitions to manual rank calculation within the service. It also adds comprehensive seed data to test these ranking scenarios and updates the associated API test collection. Feedback suggests centralizing the new sorting logic within the calculateRanks helper to ensure consistency across different statistics views and updating the API documentation in the .bru file to reflect the new response fields.

gemini-code-assist · 2026-04-30T10:35:51Z

+    leaderboard.sort((a, b) => {
+      //1순위: 맞춘 문제 개수 많을수록 상위
+      if (b.solvedProblemCount !== a.solvedProblemCount) {
+        return b.solvedProblemCount - a.solvedProblemCount
+      }
+
+      //2순위: 패널티 작을수록 상위
+      if (a.totalPenalty !== b.totalPenalty) {
+        return a.totalPenalty - b.totalPenalty
+      }
+
+      //3순위: 맞춘문제, 패널티 모두 동점일 경우 마지막 정답 제출시간 빠를수록 상위
+      const timeA = a.lastAcceptedTime?.getTime() ?? Number.MAX_SAFE_INTEGER
+      const timeB = b.lastAcceptedTime?.getTime() ?? Number.MAX_SAFE_INTEGER
+      return timeA - timeB
+    })


The sorting logic for the leaderboard has been updated to include lastAcceptedTime as a third-tier criterion. However, this logic is now inlined here, while other methods like getContestUsersStatistics and getContestUserStatistics still rely on the calculateRanks helper method which does not yet account for lastAcceptedTime. This will result in inconsistent rankings across different views (e.g., the leaderboard vs. the statistics page). It is recommended to update the calculateRanks method to include all three criteria and use it consistently throughout the service to maintain a single source of truth for ranking logic.

gemini-code-assist · 2026-04-30T10:35:52Z


 params:path {
-  id: 1
+  id: 7


While updating the contest ID for the test, the documentation for the response format (lines 37-79) was not updated to reflect the new fields added to the leaderboard records (solvedProblemCount, lastAcceptedTime). Please update the documentation to ensure it remains accurate and helpful for API consumers.

fix(be): fix contest leaderboard ranking malfunction

2e9ff4c

zero1177 requested a review from hjkim24 February 10, 2026 15:08

zero1177 self-assigned this Feb 10, 2026

zero1177 added ⛳️ team-backend 🍊squad-유자차 스쿼드 유자차 작업물입니다 labels Feb 10, 2026

zero1177 added 3 commits February 16, 2026 06:36

Merge branch 'main' into t2552-modify-contest-statistics-leaderboard

02a5250

fix(be): refatoring and test complete

653f4a5

fix(be): remove unused value

7410e4c

gemini-code-assist Bot reviewed Mar 25, 2026

View reviewed changes

fix(be): add tiebreaker logic for users with same solvedProblemCount …

5d68658

…& penalty and add seed data

gemini-code-assist Bot reviewed Apr 26, 2026

View reviewed changes

zero1177 added 2 commits April 27, 2026 11:56

Merge branch 'main' of https://github.com/skkuding/codedang into t255…

2ae45bd

…2-modify-contest-statistics-leaderboard

fix(be): add lastAcceptedTime tiebreaker logic

86f5c20

Copilot AI review requested due to automatic review settings April 27, 2026 12:59

Copilot started reviewing on behalf of zero1177 April 27, 2026 12:59 View session

gemini-code-assist Bot reviewed Apr 27, 2026

View reviewed changes

Comment thread apps/backend/apps/client/src/contest/contest.service.ts

Comment thread apps/backend/apps/client/src/contest/contest.service.ts

Comment thread apps/backend/prisma/seed.ts

Copilot AI reviewed Apr 27, 2026

View reviewed changes

fix(be): add lastAcceptedTime seed data

d569bb5

Co-authored-by: Copilot <copilot@github.com>

gemini-code-assist Bot reviewed Apr 30, 2026

View reviewed changes

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Description

변경사항

테스트

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zero1177 commented Feb 10, 2026 •

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