Problem Yearly AC Rate — Design Spec

Date: 2026-05-11
Status: Approved

Overview

Add a per-problem "historical AC rate by year" feature. A new backend API returns yearly submission statistics for a given problem; the frontend displays this as a line chart on the problem stats page, alongside the existing submission-result pie chart.

Backend

Endpoint

GET /api/problem/yearly_ac?problem_id=<_id>

Public (user-facing), no authentication required
problem_id: the problem's display ID (Problem._id, string)

Query Logic

Submission.objects.filter(
    problem_id=problem.id,
    contest_id__isnull=True,          # exclude contest submissions
    result__not_in=[JudgeStatus.PENDING, JudgeStatus.JUDGING],  # exclude in-flight submissions
)
.annotate(year=ExtractYear('create_time'))
.values('year')
.annotate(
    total=Count('id'),
    accepted=Count('id', filter=Q(result=JudgeStatus.ACCEPTED))
)
.order_by('year')

Response Format

{
  "error": null,
  "data": [
    {"year": 2023, "total": 120, "accepted": 54, "ac_rate": 45.0},
    {"year": 2024, "total": 88,  "accepted": 31, "ac_rate": 35.23}
  ]
}

ac_rate: float, two decimal places, percentage (0–100)
If total == 0 for a year: ac_rate = 0 (guards against division by zero)
Empty list returned if no judged submissions exist

Error Cases

Condition	Response
`problem_id` missing	`error("problem_id is required")`
Problem not found / not visible	`error("Problem does not exist")`

Caching

Redis cache key: problem_yearly_ac:{problem._id}
TTL: 3600 seconds (1 hour), consistent with other problem caches

Implementation Location

View class: ProblemYearlyACRateAPI in OnlineJudge/problem/views/oj.py
URL: path("problem/yearly_ac", ProblemYearlyACRateAPI.as_view()) in OnlineJudge/problem/urls/oj.py

Frontend

New Component

ojnext/src/oj/problem/components/ProblemYearlyChart.vue

Uses vue-chartjs Line chart (same library as oj/contest/components/LineChart.vue)
Registers: CategoryScale, LinearScale, PointElement, LineElement, Title, Tooltip, Filler
Props: data: Array<{ year: number; total: number; accepted: number; ac_rate: number }>
X-axis: year (string labels)
Y-axis: AC rate 0–100%
Tooltip per point: year, AC rate, accepted/total counts
Shows nothing (v-if) when data is empty or has only one point

Chart Options

responsive: true, maintainAspectRatio: false, height 250px
Dataset: fill: true (area chart feel), single line
Y-axis: min: 0, max: 100, tick suffix %

API Call

Add to ojnext/src/oj/api.ts:

export function getProblemYearlyAC(problemId: string) {
  return http.get<Array<{ year: number; total: number; accepted: number; ac_rate: number }>>(
    "/problem/yearly_ac",
    { params: { problem_id: problemId } }
  )
}

Integration

In ojnext/src/oj/problem/components/ProblemInfo.vue:

Import getProblemYearlyAC and call it on mount (alongside existing getProblemBeatRate)
Render <ProblemYearlyChart> below the existing pie chart, with a section title "历年 AC 率"
No loading spinner needed (chart simply absent until data arrives)

Assumptions

Contest submissions excluded; they represent a different access context
PENDING (6) and JUDGING (7) excluded; PARTIALLY_ACCEPTED (8) and SYSTEM_ERROR (5) are included as final verdicts
No migrations needed (query only, no model changes)

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