perf(排名): 打开排名页快一些，看「全服 · 全部」从 0.27 秒降到 0.08 秒

做对时刻在库里换成毫秒、按人聚成数组再取回，不再一行一个 timestamptz 逐条解析（全服全部历史六万多行，光解析就占 150ms）。名次与原来完全一致。 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
feat(顶栏): 导航最左边加「首页」，和点站名一样回到首页
2026-11-03 10:32:32 +08:00 · 2026-11-03 09:36:41 +08:00 · 2026-11-03 09:34:59 +08:00 · 2026-11-03 09:32:57 +08:00 · 2026-11-03 09:26:39 +08:00 · 2026-11-03 09:05:23 +08:00
18 changed files with 297 additions and 182 deletions
@@ -1,4 +1,4 @@
-import { adminLessonRequestSchema, STUDENT_ROLES, type AdminLessonList, type AdminLessonRequest } from '@oj2/contract'
+import { adminLessonRequestSchema, lessonModeSchema, STUDENT_ROLES, type AdminLessonList, type AdminLessonRequest } from '@oj2/contract'
 import { and, count, desc, eq, inArray, sql } from 'drizzle-orm'
 import { Hono } from 'hono'

@@ -24,7 +24,12 @@ adminLessonRoutes.get('/lessons', requireTeacher, async (c) => {
  const offset = queryInteger(c.req.query('offset'), 0, { min: 0 })
  const className = c.req.query('className')?.trim()
  const teacherId = queryInteger(c.req.query('teacher'), 0, { min: 0 })
-  const where = and(className ? eq(schema.classLesson.className, className) : undefined, teacherId ? eq(schema.classLesson.createdBy, teacherId) : undefined)
+  const mode = lessonModeSchema.safeParse(c.req.query('mode')).data
+  const where = and(
+    className ? eq(schema.classLesson.className, className) : undefined,
+    teacherId ? eq(schema.classLesson.createdBy, teacherId) : undefined,
+    mode ? eq(schema.classLesson.mode, mode) : undefined,
+  )

  const [rows, [totalRow], teachers] = await Promise.all([
    db
@@ -156,10 +161,14 @@ adminLessonRoutes.put('/lessons/:id', requireTeacher, async (c) => {
  // 班级能改：原来那个班和新的班学生看到的都可能变，两边各比一次
  const classes = await affectedClasses(id, result.values.className)
  const before = await Promise.all(classes.map((className) => todayLessonSnapshot(className)))
+  // 时刻只填到分：没改时刻就留着原来带秒的那个。不然只改了做什么，这一节也被挪到这一分钟的开头，
+  // 排到同一分钟里后布置的那节前面去 —— 「今天最后一节」就换了人（先画流程图、紧接着再开一节写代码，常在同一分钟里）
+  const [current] = await db.select({ createdAt: schema.classLesson.createdAt }).from(schema.classLesson).where(eq(schema.classLesson.id, id))
+  const sameMinute = current && Math.floor(Date.parse(current.createdAt) / 60_000) * 60_000 === Date.parse(result.values.createdAt)
  // 布置的老师不换，和任务页上「改」一样认第一次
  const [row] = await db
    .update(schema.classLesson)
-    .set({ ...result.values, updatedAt: new Date().toISOString() })
+    .set({ ...result.values, createdAt: sameMinute ? current.createdAt : result.values.createdAt, updatedAt: new Date().toISOString() })
    .where(eq(schema.classLesson.id, id))
    .returning({ id: schema.classLesson.id })
  if (!row) return failure(c, 404, 'lesson-not-found', '这一节已经被删掉了')
@@ -1,5 +1,5 @@
-import { type ClassActivity, type ClassActivityProblem, type LastVisit, type LessonLanguage, type LessonMode, lessonNeeds } from '@oj2/contract'
-import { and, asc, desc, eq, gte, inArray, isNull, lt, sql } from 'drizzle-orm'
+import { type ClassActivity, type ClassActivityProblem, type LastVisit } from '@oj2/contract'
+import { and, asc, eq, gte, inArray, isNull, lt, sql } from 'drizzle-orm'
 import { Hono } from 'hono'

 import { requireAuth, type AppEnv } from '../auth/middleware'
@@ -9,7 +9,6 @@ import { success } from '../http'
 import { FLOWCHART_PASSED, lessonLanguageFilter, SOLVED_RESULTS } from '../services/class-activity'
 import { accepted } from '../services/learning-stats'
 import { CLASS_ACTIVITY_LOOKBACK_DAYS, classLessonProblems } from '../services/lesson'
-import { calendarDay } from '../time'

 /**
 * 首页上和「这节课」有关的两张卡：学生的「上次来」和「班里在做」。
@@ -145,7 +144,7 @@ homeRoutes.get('/me/class-activity', requireAuth, async (c) => {

  const lesson = await classLessonProblems(user.className, CLASS_ACTIVITY_LOOKBACK_DAYS)
  const ids = lesson.problems.map((problem) => problem.id)
-  const steps = lesson.source === 'teacher' && lesson.mode ? await todaySteps(user.className, ids, lesson) : null
+  const steps = lesson.steps
  const codeLanguage = steps ? steps.language : lesson.language
  // 代码提交和流程图提交两张表，互不依赖，一起查
  const [mine, drawn] = await Promise.all([
@@ -193,7 +192,7 @@ homeRoutes.get('/me/class-activity', requireAuth, async (c) => {
    problems: lesson.problems.map((problem) => {
      const code = stepOf(codeById.get(problem.id))
      const draw = stepOf(drawById.get(problem.id))
-      const needs = steps?.needs.get(problem.id)
+      const needs = steps?.needsOf(problem.id)
      let myStatus: Step
      if (needs) {
        // 老师布置的：要哪几步就看哪几步，全做到才算做完
@@ -215,39 +214,3 @@ homeRoutes.get('/me/class-activity', requireAuth, async (c) => {
    }),
  } satisfies ClassActivity)
 })
-
-/**
- * 学生那边一道题要画还是要写：今天这个班布置过的每一节里，凡是有这道题的，要求合起来算。
- * 老师先布置一节画流程图、再布置一节同样的题写代码时，还没画完的人照样看得到要画 ——
- * 学生只看得到今天最后布置的那一节，不合起来的话，画流程图那节一布置写代码就没了。
- *
- * 写代码用的语言：今天最后布置的、要写代码的那一节选的（只画流程图的课没有语言）
- */
-async function todaySteps(
-  className: string,
-  problemIds: number[],
-  latest: { lessonId: number | null; language: LessonLanguage | null; mode: LessonMode | null },
-) {
-  const rows = await db
-    .select({ id: schema.classLesson.id, problemIds: schema.classLesson.problemIds, language: schema.classLesson.language, mode: schema.classLesson.mode })
-    .from(schema.classLesson)
-    .where(and(eq(schema.classLesson.className, className), eq(schema.classLesson.day, calendarDay())))
-    .orderBy(desc(schema.classLesson.createdAt), desc(schema.classLesson.id))
-  const needs = new Map<number, { draw: boolean; code: boolean }>()
-  let language: LessonLanguage | null = latest.mode && lessonNeeds(latest.mode).code ? latest.language : null
-  let languageFound = !!latest.mode && lessonNeeds(latest.mode).code
-  for (const row of rows) {
-    const shared = row.id === latest.lessonId ? problemIds : row.problemIds.filter((id) => problemIds.includes(id))
-    if (!shared.length) continue
-    const rowNeeds = lessonNeeds(row.mode)
-    for (const id of shared) {
-      const known = needs.get(id) ?? { draw: false, code: false }
-      needs.set(id, { draw: known.draw || rowNeeds.draw, code: known.code || rowNeeds.code })
-    }
-    if (!languageFound && rowNeeds.code) {
-      language = row.language ?? null
-      languageFound = true
-    }
-  }
-  return { needs, language }
-}
@@ -252,14 +252,7 @@ rankingRoutes.get('/rankings/champions', optionalAuth, async (c) => {
  const champions: WeeklyChampion[] = []
  for (let k = 1; k <= CHAMPION_WEEKS; k++) {
    const from = thisWeek - k * WEEK_MS
-    const inWeek = entrants.map((entrant) => {
-      const keep = entrant.times.map((time, index) => [time, entrant.stamps[index]!] as const).filter(([time]) => time >= from && time < from + WEEK_MS)
-      return {
-        ...entrant,
-        times: keep.map(([time]) => time),
-        stamps: keep.map(([, stamp]) => stamp),
-      }
-    })
+    const inWeek = entrants.map((entrant) => ({ ...entrant, times: entrant.times.filter((time) => time >= from && time < from + WEEK_MS) }))
    const [top] = standings(inWeek, null, false)
    if (!top) continue
    champions.push({
@@ -527,6 +527,11 @@ const LESSON_LIVE_MINUTES = 15
 /** 一次列多少节课。「一节课」「今天」一般一两行，「这学期」「全部」有几百节，先给最近的这些 */
 const LESSONS_DEFAULT = 50
 const LESSONS_MAX = 500
+/** 课只算学生（STUDENT_ROLES，学生管理员也算），老师试题的提交不算 */
+const studentRoles = sql.join(
+  STUDENT_ROLES.map((role) => sql`${role}`),
+  sql`, `,
+)

 type StatisticsRange = { start: string | null; end: string }

@@ -599,7 +604,7 @@ async function assignedLessons(plans: LessonPlan[], range: StatisticsRange) {
        where s.contest_id is null and p.mode <> 'flowchart'
          and s.create_time <= ${range.end}
          ${range.start ? sql`and s.create_time >= ${range.start}` : sql``}
-          and u.admin_type = 'Regular User' and u.is_disabled = false
+          and u.admin_type in (${studentRoles}) and u.is_disabled = false
        union all
        select p.k, f.user_id, f.problem_id, (f.status = 2 and coalesce(f.ai_grade in (${sql.join(
          FLOWCHART_PASS_GRADES.map((grade) => sql`${grade}`),
@@ -612,7 +617,7 @@ async function assignedLessons(plans: LessonPlan[], range: StatisticsRange) {
        where p.mode <> 'code'
          and f.create_time <= ${range.end}
          ${range.start ? sql`and f.create_time >= ${range.start}` : sql``}
-          and u.admin_type = 'Regular User' and u.is_disabled = false
+          and u.admin_type in (${studentRoles}) and u.is_disabled = false
      )
      select k, problem_id,
        count(distinct user_id)::int as users,
@@ -721,8 +726,8 @@ submissionStatisticsRoutes.get('/submissions/statistics/lessons', requireTeacher
      where s.contest_id is null
        and s.create_time <= ${range.end}
        ${range.start ? sql`and s.create_time >= ${range.start}` : sql``}
-        -- 只算普通学生：老师试题的提交不该把一段拼成「一节课」
-        and u.admin_type = 'Regular User' and u.is_disabled = false
+        -- 只算学生（学生管理员也是学生）：老师试题的提交不该把一段拼成「一节课」
+        and u.admin_type in (${studentRoles}) and u.is_disabled = false
    ),
    g as (
      select *,
@@ -5,7 +5,6 @@ import {
  type TaskBoard,
  type TaskBoardStudent,
  type ClassLesson,
-  lessonNeeds,
  type StatisticInfo,
 } from '@oj2/contract'
 import { and, desc, eq, gte, inArray, isNotNull, isNull, sql } from 'drizzle-orm'
@@ -127,9 +126,14 @@ taskRoutes.get('/task/board', requireTeacher, async (c) => {
  const challengeDoneKeys = new Set(
    challengeDone.filter((row) => liveChallenges.get(row.problemId)?.has(row.challengeId)).map((row) => `${row.userId}:${row.problemId}`),
  )
-  // 老师布置的这节做什么；推断出来的课为 null，代码交对或流程图画对都算（和加「做什么」之前一样）
+  // 老师布置的这节做什么；推断出来的课为 null，代码交对或流程图画对都算（和加「做什么」之前一样）。
+  // 格子按每道题合起来的要求算（todayNeeds）：先画流程图一节、再写代码一节，没画图的照样标「缺图」，
+  // 和学生那边的「做完」对得上。代码按的语言也是合起来那份：最后一节只画流程图时，用前面写代码那节的
  const mode = lesson.source === 'teacher' ? lesson.mode : null
-  const needs = mode ? lessonNeeds(mode) : null
+  const steps = lesson.steps
+  const needsOf = (problemId: number) => steps?.needsOf(problemId) ?? null
+  const anyDraw = ids.some((id) => needsOf(id)?.draw)
+  const codeLanguage = steps ? steps.language : lesson.language
  const [cells, lastSubmits, lastDrawn, attendance, drawn, todays, seen, lastFlows] = await Promise.all([
    ids.length && userIds.length
      ? db
@@ -145,7 +149,7 @@ taskRoutes.get('/task/board', requireTeacher, async (c) => {
              isNull(schema.submission.contestId),
              inArray(schema.submission.userId, userIds),
              inArray(schema.submission.problemId, ids),
-              lessonLanguageFilter(lesson.language),
+              lessonLanguageFilter(codeLanguage),
            ),
          )
          .groupBy(schema.submission.userId, schema.submission.problemId)
@@ -223,7 +227,7 @@ taskRoutes.get('/task/board', requireTeacher, async (c) => {
              inArray(schema.submission.userId, userIds),
              inArray(schema.submission.problemId, ids),
              gte(schema.submission.createTime, start),
-              lessonLanguageFilter(lesson.language),
+              lessonLanguageFilter(codeLanguage),
            ),
          )
          .orderBy(schema.submission.createTime)
@@ -234,7 +238,7 @@ taskRoutes.get('/task/board', requireTeacher, async (c) => {
     * 还没画对的格子点开讲它哪里错、按走对几组归堆。走对几组从 2026-10 起的「走例子」报告里数，
     * 老评法和还没评完的为 null
     */
-    needs?.draw && ids.length && userIds.length
+    anyDraw && ids.length && userIds.length
      ? db
          .selectDistinctOn([schema.flowchartSubmission.userId, schema.flowchartSubmission.problemId], {
            userId: schema.flowchartSubmission.userId,
@@ -281,6 +285,7 @@ taskRoutes.get('/task/board', requireTeacher, async (c) => {
      title: problem.title,
      isSql: problem.isSql,
      hasChallenges: (liveChallenges.get(problem.id)?.size ?? 0) > 0,
+      mode: steps?.modeOf(problem.id) ?? null,
    })),
    students: roster.map(
      (student) =>
@@ -289,6 +294,7 @@ taskRoutes.get('/task/board', requireTeacher, async (c) => {
          username: student.username,
          realName: student.realName ?? null,
          cells: ids.map((id) => {
+            const needs = needsOf(id)
            const key = `${student.userId}:${id}`
            const cell = cellByKey.get(key)
            const flow = drawnByKey.get(key)
@@ -305,11 +311,11 @@ taskRoutes.get('/task/board', requireTeacher, async (c) => {
              attempts = (cell?.attempts ?? 0) + (flow?.attempts ?? 0)
            } else {
              // 要哪几步看哪几步：两步都做到的时刻是晚的那一步
-              const steps = [needs.draw ? { status: drawStatus, at: flowAt } : null, needs.code ? { status: codeStatus, at: codeAt } : null].filter(
+              const wanted = [needs.draw ? { status: drawStatus, at: flowAt } : null, needs.code ? { status: codeStatus, at: codeAt } : null].filter(
                (step) => step !== null,
              )
-              acceptedAt = steps.every((step) => step.at) ? steps.map((step) => step.at!).reduce(latestOf) : null
-              status = acceptedAt ? 'accepted' : steps.some((step) => step.status !== 'none') ? 'tried' : 'none'
+              acceptedAt = wanted.every((step) => step.at) ? wanted.map((step) => step.at!).reduce(latestOf) : null
+              status = acceptedAt ? 'accepted' : wanted.some((step) => step.status !== 'none') ? 'tried' : 'none'
              attempts = (needs.code ? (cell?.attempts ?? 0) : 0) + (needs.draw ? (flow?.attempts ?? 0) : 0)
            }
            // 下面几样都是代码那一步的：只画流程图的课没有
@@ -352,8 +358,9 @@ taskRoutes.get('/task/board', requireTeacher, async (c) => {
                  }))
                : [],
              acceptedTry: firstTry >= 0 ? firstTry + 1 : null,
+              // 整道题做完了才谈挑战：先画再写只交对了代码、图还没画的，格子是「缺图」，不挂挑战的圈
              challenge:
-                !codeWanted || !codeDone || !liveChallenges.get(id)?.size
+                !codeWanted || !codeDone || !acceptedAt || !liveChallenges.get(id)?.size
                  ? null
                  : challengeDoneKeys.has(key)
                    ? 'done'
@@ -410,9 +417,17 @@ taskRoutes.get('/task/today', requireTeacher, async (c) => {
      const ids = lesson.problems.map((problem) => problem.id)
      let allDoneCount = 0
      if (ids.length && lesson.source === 'teacher' && lesson.lessonId && lesson.mode) {
-        // 老师布置的：和任务页、后台课堂任务同一个口径（要画的看图、要写的看代码）
+        // 老师布置的：和任务页同一个口径（每道题按今天几节合起来的要求，要画的看图、要写的看代码）
        const counts = await lessonDoneCounts([
-          { id: lesson.lessonId, className, day: calendarDay(), problemIds: ids, language: lesson.language, mode: lesson.mode },
+          {
+            id: lesson.lessonId,
+            className,
+            day: calendarDay(),
+            problemIds: ids,
+            language: lesson.steps?.language ?? lesson.language,
+            mode: lesson.mode,
+            modeOf: lesson.steps?.modeOf,
+          },
        ])
        allDoneCount = counts.get(lesson.lessonId) ?? 0
      } else if (ids.length) {
@@ -59,7 +59,16 @@ export function lessonDayEnd(day: string) {
 * 人按花名册（STUDENT_ROLES、没禁用），和「全班几人」对得上
 */
 export async function lessonDoneCounts(
-  lessons: { id: number; className: string; day: string; problemIds: number[]; language: LessonLanguage | null; mode: LessonMode }[],
+  lessons: {
+    id: number
+    className: string
+    day: string
+    problemIds: number[]
+    language: LessonLanguage | null
+    mode: LessonMode
+    /** 每道题各自做什么（老师首页按今天几节合起来的要求算，见 todayNeeds）；不给就都按 mode */
+    modeOf?: (problemId: number) => LessonMode
+  }[],
 ) {
  const rows = lessons.flatMap((lesson) =>
    lesson.problemIds.map((problemId) => ({
@@ -67,7 +76,7 @@ export async function lessonDoneCounts(
      class_name: lesson.className,
      problem_id: problemId,
      language: lesson.language,
-      mode: lesson.mode,
+      mode: lesson.modeOf?.(problemId) ?? lesson.mode,
      until: lessonDayEnd(lesson.day),
    })),
  )
@@ -281,6 +290,45 @@ async function lessonPlan(className: string, day: string) {
  return row?.problemIds.length ? row : null
 }

+/**
+ * 一道题今天要画还是要写：这个班今天布置过的每一节里，凡是有这道题的，要求合起来算。
+ * 老师先布置一节画流程图、再「用这几道题写代码」开一节时，还没画完的照样要画 ——
+ * 只看今天最后布置的那一节的话，一布置写代码，画图那一步就没了。学生的课堂条、任务页的格子、
+ * 老师首页的「全做对」都按它算，三处说的「做完」才一样（后台和数据统计还是一节一行、各数各的）。
+ *
+ * `language`：代码按什么语言数 —— 今天最后布置的、要写代码的那一节选的（只画流程图的课没有语言）
+ */
+export async function todayNeeds(className: string, problemIds: number[], latest: { id: number; language: LessonLanguage | null; mode: LessonMode }) {
+  const rows = await db
+    .select({ id: schema.classLesson.id, problemIds: schema.classLesson.problemIds, language: schema.classLesson.language, mode: schema.classLesson.mode })
+    .from(schema.classLesson)
+    .where(and(eq(schema.classLesson.className, className), eq(schema.classLesson.day, calendarDay())))
+    .orderBy(desc(schema.classLesson.createdAt), desc(schema.classLesson.id))
+  const needs = new Map<number, { draw: boolean; code: boolean }>()
+  let language: LessonLanguage | null = lessonNeeds(latest.mode).code ? latest.language : null
+  let languageFound = lessonNeeds(latest.mode).code
+  for (const row of rows) {
+    const shared = row.id === latest.id ? problemIds : row.problemIds.filter((id) => problemIds.includes(id))
+    if (!shared.length) continue
+    const rowNeeds = lessonNeeds(row.mode)
+    for (const id of shared) {
+      const known = needs.get(id) ?? { draw: false, code: false }
+      needs.set(id, { draw: known.draw || rowNeeds.draw, code: known.code || rowNeeds.code })
+    }
+    if (!languageFound && rowNeeds.code) {
+      language = row.language ?? null
+      languageFound = true
+    }
+  }
+  const latestNeeds = lessonNeeds(latest.mode)
+  const needsOf = (id: number) => needs.get(id) ?? latestNeeds
+  const modeOf = (id: number): LessonMode => {
+    const { draw, code } = needsOf(id)
+    return draw && code ? 'both' : draw ? 'flowchart' : 'code'
+  }
+  return { needsOf, modeOf, language }
+}
+
 /**
 * 班里「这节课」的题。老师在课堂任务布置过就用老师的（source = teacher），
 * 否则从同班提交记录推断（source = inferred）：同班同一天 ≥ 5 人做过的题，只取最近的
@@ -294,17 +342,23 @@ export async function classLessonProblems(className: string, lookbackDays: numbe
  const plan = await lessonPlan(className, today)
  if (plan) {
    const planned = plan.problemIds
-    const [problems, groups] = await Promise.all([
+    const steps = await todayNeeds(className, planned, plan)
+    // 每道题按它合起来的要求数「做过 / 做对」：要求一样的几道一起数
+    const byMode = Map.groupBy(planned, (id) => steps.modeOf(id))
+    const [problems, ...groupLists] = await Promise.all([
      visibleProblems(planned),
-      classDayGroups(className, dayStart(), { problemIds: planned, language: plan.language, mode: plan.mode }),
+      ...[...byMode].map(([mode, ids]) =>
+        classDayGroups(className, dayStart(), { problemIds: ids, language: lessonNeeds(mode).code ? steps.language : null, mode }),
+      ),
    ])
-    const groupById = new Map(groups.map((row) => [row.problemId, row]))
+    const groupById = new Map(groupLists.flat().map((row) => [row.problemId, row]))
    return {
      source: 'teacher' as const,
      lessonId: plan.id,
      day: today,
      language: plan.language ?? null,
      mode: plan.mode,
+      steps,
      assignedAt: plan.createdAt,
      assignedBy: plan.createdBy,
      problems: planned.flatMap((id) => {
@@ -337,6 +391,7 @@ export async function classLessonProblems(className: string, lookbackDays: numbe
    // 推断出来的课不知道老师要的是哪种语言、要画还是要写，不限
    language: null,
    mode: null,
+    steps: null,
    assignedAt: null,
    assignedBy: null,
    problems: picked.flatMap((row) => {
@@ -36,9 +36,8 @@ export interface Entrant {
  className: string | null
  avatar: string | null
  mood: string | null
-  /** 每道题第一次做对的时刻，升序；毫秒数用来比较，原文留着给出参 */
+  /** 每道题第一次做对的时刻（毫秒），升序 */
  times: number[]
-  stamps: string[]
 }

 export interface Standing {
@@ -64,10 +63,26 @@ export function avatarOf(avatar: string | null) {
 * 先按 (人, 题) 取全部历史里的最早一次，再用 having 卡 `>= since` —— 这样「这学期」数的是
 * 这学期**第一次**做对的题，以前做对过的老题这学期重交一遍不算。比赛里的提交不算。
 * 走 `submission_public_metrics_idx`（user_id, problem_id, result, create_time，WHERE
- * contest_id IS NULL），全服全部历史实测 24ms。
+ * contest_id IS NULL）。
+ *
+ * 时刻在库里就换成毫秒数、按人排好聚成数组再拿回来：全服全部历史有六万多个 (人, 题)，
+ * 一行一个 timestamptz 的话，光 db/index.ts 那个保留微秒的 parser 加 `Date.parse` 就
+ * 要 150ms（两核上），库里的查询本身才 40ms。截到毫秒和原来 `Date.parse` 比较的精度一样，
+ * 名次不变；`reachedAt` 只拿来显示「比你早多久」，用不着微秒。
 */
 export async function loadEntrants(where: SQL, since: string | null): Promise<Entrant[]> {
  const firstSolved = min(schema.submission.createTime)
+  const firsts = db
+    .select({
+      userId: schema.submission.userId,
+      at: sql<number>`floor(extract(epoch from ${firstSolved}) * 1000)::float8`.as('at'),
+    })
+    .from(schema.submission)
+    .innerJoin(schema.user, eq(schema.user.id, schema.submission.userId))
+    .where(and(where, isNull(schema.submission.contestId), inArray(schema.submission.result, SOLVED_RESULTS)))
+    .groupBy(schema.submission.userId, schema.submission.problemId)
+    .having(since ? gte(firstSolved, since) : undefined)
+    .as('firsts')
  const [people, solves] = await Promise.all([
    db
      .select({
@@ -81,33 +96,20 @@ export async function loadEntrants(where: SQL, since: string | null): Promise<En
      .leftJoin(schema.userProfile, eq(schema.userProfile.userId, schema.user.id))
      .where(where),
    db
-      .select({ userId: schema.submission.userId, at: firstSolved })
-      .from(schema.submission)
-      .innerJoin(schema.user, eq(schema.user.id, schema.submission.userId))
-      .where(and(where, isNull(schema.submission.contestId), inArray(schema.submission.result, SOLVED_RESULTS)))
-      .groupBy(schema.submission.userId, schema.submission.problemId)
-      .having(since ? gte(firstSolved, since) : undefined),
+      .select({ userId: firsts.userId, times: sql<number[]>`array_agg(${firsts.at} order by ${firsts.at})` })
+      .from(firsts)
+      .groupBy(firsts.userId),
  ])

-  const byUser = new Map<number, string[]>()
-  for (const row of solves) {
-    if (!row.at) continue
-    const list = byUser.get(row.userId)
-    if (list) list.push(row.at)
-    else byUser.set(row.userId, [row.at])
-  }
-  return people.map((person) => {
-    const pairs = (byUser.get(person.id) ?? []).map((stamp) => [Date.parse(stamp), stamp] as const).sort((a, b) => a[0] - b[0])
-    return {
-      id: person.id,
-      username: person.username,
-      className: person.className,
-      avatar: avatarOf(person.avatar),
-      mood: person.mood?.trim() || null,
-      times: pairs.map(([time]) => time),
-      stamps: pairs.map(([, stamp]) => stamp),
-    }
-  })
+  const byUser = new Map(solves.map((row) => [row.userId, row.times]))
+  return people.map((person) => ({
+    id: person.id,
+    username: person.username,
+    className: person.className,
+    avatar: avatarOf(person.avatar),
+    mood: person.mood?.trim() || null,
+    times: byUser.get(person.id) ?? [],
+  }))
 }

 /**
@@ -127,7 +129,7 @@ export function standings(entrants: Entrant[], cutoff: number | null, includeZer
        entrant,
        solved,
        reached: solved ? entrant.times[solved - 1]! : Number.POSITIVE_INFINITY,
-        reachedAt: solved ? entrant.stamps[solved - 1]! : null,
+        reachedAt: solved ? new Date(entrant.times[solved - 1]!).toISOString() : null,
      }
    })
    .filter((row) => includeZero || row.solved > 0)
@@ -786,9 +786,9 @@ export function deleteAchievement(id: number) {

 // ---------- 课堂任务（class_lesson） ----------

-export function getAdminLessons(offset: number, limit: number, filters: { className: string; teacher: number | null }) {
+export function getAdminLessons(offset: number, limit: number, filters: { className: string; teacher: number | null; mode: string }) {
  return api.get<AdminLessonList>('admin/lessons', {
-    params: { offset, limit, className: filters.className, teacher: filters.teacher ?? '' },
+    params: { offset, limit, className: filters.className, teacher: filters.teacher ?? '', mode: filters.mode },
  })
 }

@@ -1,8 +1,8 @@
 <script setup lang="ts">
-import { LESSON_MODE_LABEL, type AdminLesson, type AdminLessonList } from '@oj2/contract'
+import { LESSON_MODE_LABEL, type AdminLesson, type AdminLessonList, type LessonMode } from '@oj2/contract'
 import { useRouteQuery } from '@vueuse/router'
 import PageHeader from 'admin/components/PageHeader.vue'
-import { NButton, NPopconfirm, NTooltip, useThemeVars } from 'naive-ui'
+import { NButton, NPopconfirm, NTag, NTooltip, useThemeVars } from 'naive-ui'
 import { dayStartOfDate } from 'oj/statistics/period'
 import Pagination from 'shared/components/Pagination.vue'
 import { useBreakpoints } from 'shared/composables/breakpoints'
@@ -27,13 +27,16 @@ const configStore = useConfigStore()
 const { isMobile } = useBreakpoints()

 // 从任务页「布置过的课」进来带着 ?className=
-const { query } = usePagination<{ className: string; teacher: string }>({
+const { query } = usePagination<{ className: string; teacher: string; mode: string }>({
  className: useRouteQuery('className', '').value,
  teacher: useRouteQuery('teacher', '').value,
+  mode: useRouteQuery('mode', '').value,
 })
 const data = ref<AdminLessonList | null>(null)

 const classOptions = computed(() => [{ label: '全部班级', value: '' }, ...groupClassOptions(configStore.config?.classList ?? [])])
+const MODES: LessonMode[] = ['code', 'both', 'flowchart']
+const modeOptions = [{ label: '全部做法', value: '' }, ...MODES.map((value) => ({ label: LESSON_MODE_LABEL[value], value }))]
 const teacherOptions = computed(() => [
  { label: '全部老师', value: '' },
  ...(data.value?.teachers ?? []).map((teacher) => ({ label: teacher.name, value: String(teacher.id) })),
@@ -46,13 +49,14 @@ async function list() {
    getAdminLessons((query.page - 1) * query.limit, query.limit, {
      className: query.className,
      teacher: query.teacher ? Number(query.teacher) : null,
+      mode: query.mode,
    }),
  )
  if (res) data.value = res
 }
 onMounted(list)
-// 换了班级、老师 usePagination 会把页码拨回 1，同一拍里只拉一次
-watch(() => [query.page, query.limit, query.className, query.teacher], list)
+// 换了班级、老师、做法 usePagination 会把页码拨回 1，同一拍里只拉一次
+watch(() => [query.page, query.limit, query.className, query.teacher, query.mode], list)

 // ---- 改 / 补 / 删 ----
 const editing = ref(false)
@@ -133,17 +137,24 @@ function renderActions(lesson: AdminLesson) {
  ])
 }

-/** 「画流程图」「先画再写 · C语言」「C语言」：写代码是默认的，不写出来 */
-function wayText(lesson: AdminLesson) {
-  return [lesson.mode !== 'code' ? LESSON_MODE_LABEL[lesson.mode] : '', lesson.language ? LANGUAGE_SHOW_VALUE[lesson.language] : ''].filter(Boolean).join(' · ')
+/** 三种做法各一个颜色，一眼分得开；写代码也写出来，不当默认值省掉 */
+const MODE_TAG_TYPE: Record<LessonMode, 'default' | 'info' | 'warning'> = { code: 'default', both: 'info', flowchart: 'warning' }
+
+/** 「写代码 C语言」「先画再写 Python」「画流程图」：画流程图不用语言 */
+function renderWay(lesson: AdminLesson) {
+  return h('div', { class: 'way' }, [
+    h(NTag, { size: 'small', bordered: false, type: MODE_TAG_TYPE[lesson.mode] }, { default: () => LESSON_MODE_LABEL[lesson.mode] }),
+    lesson.language ? h('span', { class: 'way-lang' }, LANGUAGE_SHOW_VALUE[lesson.language]) : null,
+  ])
 }

-/** 手机上一节课一张卡：日子 · 时刻 · 班级一行，题号一行，老师 · 语言 · 做完一行小字，操作一行 */
+/** 手机上一节课一张卡：日子 · 时刻 · 班级一行，做什么一行，题号一行，老师 · 做完一行小字，操作一行 */
 function renderMobileCard(lesson: AdminLesson) {
  return h('div', { class: 'm-card' }, [
    h('div', { class: 'm-head' }, `${dayText(lesson.day)} ${parseTime(lesson.createdAt, 'HH:mm')} · ${classLabel(lesson.className)}`),
+    renderWay(lesson),
    renderProblems(lesson),
-    h('div', { class: 'm-meta' }, [lesson.createdBy, wayText(lesson), `做完 ${renderDone(lesson)}`].filter(Boolean).join(' · ')),
+    h('div', { class: 'm-meta' }, `${lesson.createdBy} · 做完 ${renderDone(lesson)}`),
    renderActions(lesson),
  ])
 }
@@ -153,7 +164,7 @@ const desktopColumns: DataTableColumn<AdminLesson>[] = [
  { title: '布置', key: 'createdAt', width: 70, render: (row) => parseTime(row.createdAt, 'HH:mm') },
  { title: '班级', key: 'className', width: 130, render: (row) => classLabel(row.className) },
  { title: '老师', key: 'createdBy', width: 90 },
-  { title: '做什么', key: 'language', width: 120, render: (row) => wayText(row) || '—' },
+  { title: '做什么', key: 'mode', width: 150, render: renderWay },
  { title: '题目', key: 'problems', width: 300, render: renderProblems },
  { title: '做完 / 全班', key: 'doneCount', width: 100, render: renderDone },
  { title: '', key: 'actions', render: renderActions },
@@ -173,6 +184,7 @@ const columns = computed(() => (isMobile.value ? mobileColumns : desktopColumns)
    <template #filters>
      <n-select v-model:value="query.className" :options="classOptions" filterable aria-label="班级" :style="{ width: isMobile ? '100%' : '160px' }" />
      <n-select v-model:value="query.teacher" :options="teacherOptions" aria-label="老师" :style="{ width: isMobile ? '100%' : '140px' }" />
+      <n-select v-model:value="query.mode" :options="modeOptions" aria-label="做什么" :style="{ width: isMobile ? '100%' : '120px' }" />
    </template>
  </PageHeader>
  <n-data-table :loading="loading" striped class="lesson-table" :columns="columns" :data="data?.results ?? []" :row-key="(row: AdminLesson) => row.id" />
@@ -205,6 +217,13 @@ const columns = computed(() => (isMobile.value ? mobileColumns : desktopColumns)
  text-decoration: line-through;
 }

+.lesson-table :deep(.way) {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  white-space: nowrap;
+}
+
 .lesson-table :deep(.actions) {
  display: flex;
  gap: 8px;
@@ -7,6 +7,7 @@ import { getClassActivity } from 'shared/api'
 import SubmissionResultTag from 'shared/components/SubmissionResultTag.vue'
 import { pickHeadline, type Headline } from 'oj/user/knowledge'
 import { useUserStore } from 'shared/store/user'
+import { activityMode } from 'shared/store/lesson'
 import { ContestStatus, CONTEST_STATUS, JUDGE_STATUS, LANGUAGE_SHOW_VALUE } from 'utils/constants'
 import { duration, parseTime, zonedParts, zonedYear } from 'utils/functions'
 import type { AnnouncementListItem, ClassActivity, ClassActivityProblem, Contest, LastVisit, SubmissionListItem, WeeklyRank } from 'utils/types'
@@ -191,7 +192,7 @@ const classActivityTitle = computed(() => {
  // 老师在课堂任务布置的，说成「老师布置的」，比「班里在做」更让人知道该做这几道
  if (classActivity.value?.source === 'teacher') {
    const language = classActivity.value.language
-    const mode = classActivity.value.mode
+    const mode = activityMode(classActivity.value)
    if (mode === 'flowchart') return '这节课 · 画流程图'
    if (mode === 'both') return `这节课 · 先画流程图，再${language ? `用${LANGUAGE_SHOW_VALUE[language]}` : ''}写代码`
    return `这节课${language ? ` · 用${LANGUAGE_SHOW_VALUE[language]}做` : ''}`
@@ -73,12 +73,15 @@ watch(
  () => (myFlowchartOpen.value = true),
 )

-/** 流程图画到 A / S 了：标题下给个「流程图 A 级」 */
+/**
+ * 标题下的「流程图 X 级」：评完过的里面最好的那一次。画到 A / S 是绿的（算做完了），
+ * 没画到是橙的 —— 原来只在 A / S 时才写，画到 C 的学生标题下是「还没交过」，像是什么都没交
+ */
 const flowchartGrade = computed(() => {
-  const passed = flowchartStore.scores.filter((row) => isFlowchartPass(row.grade))
-  if (!passed.length) return ''
-  return passed.some((row) => row.grade === 'S') ? 'S' : 'A'
+  const best = flowchartStore.scores.reduce<(typeof flowchartStore.scores)[number] | null>((acc, row) => (!acc || row.score > acc.score ? row : acc), null)
+  return best?.grade ?? ''
 })
+const flowchartPassed = computed(() => isFlowchartPass(flowchartGrade.value))

 // 例子旁的「复制」：点完变成「已复制」一秒
 const message = useMessage()
@@ -192,12 +195,13 @@ const astRequirements = computed(() => Object.entries(problem.value?.astRequirem
        </n-tag>
        <n-tag v-if="myStatus === 'solved'" size="small" type="success" :bordered="false"> 已解决 </n-tag>
        <!-- 流程图画到 A / S 就算做完了（决定 4）：别在「流程图 A 级」旁边再写「还没交过」
-             「做过，还没对」—— 那两个说的是代码 -->
-        <template v-else-if="!flowchartGrade">
+             「做过，还没对」—— 那两个说的是代码。图没画到 A 的，代码交过没对照写；没交过代码就不写
+             「还没交过」，旁边的「流程图 C 级」已经说了交过什么 -->
+        <template v-else-if="!flowchartPassed">
          <n-tag v-if="myStatus === 'tried'" size="small" type="warning" :bordered="false"> 做过，还没对 </n-tag>
-          <n-tag v-else-if="myStatus === 'none'" size="small" :bordered="false">还没交过</n-tag>
+          <n-tag v-else-if="myStatus === 'none' && !flowchartGrade" size="small" :bordered="false">还没交过</n-tag>
        </template>
-        <n-tag v-if="flowchartGrade" size="small" type="success" :bordered="false"> 流程图 {{ flowchartGrade }} 级 </n-tag>
+        <n-tag v-if="flowchartGrade" size="small" :type="flowchartPassed ? 'success' : 'warning'" :bordered="false"> 流程图 {{ flowchartGrade }} 级 </n-tag>
      </div>
    </header>

@@ -182,16 +182,25 @@ watch(
 * 没有画这一步的课，画着流程图时不动他
 */
 const lessonStore = useLessonStore()
-let lessonLanguageFor: string | null = null
+/**
+ * 换过的（题 + 这一节 + 该做的那一步）都记下：换到别的题再回来，同一步不再换第二次。
+ * 编辑器在换题时不重新挂载（detail.vue 只重新 init），只记最后一个的话一回来又被拽回去
+ */
+const lessonSwitched = new Set<string>()
+let lessonViewing: string | null = null
 watch(
  () => [problem.value?._id, lessonStore.activity] as const,
  ([id, activity]) => {
    if (!id || !activity) return
-    const key = [id, activity.day, activity.mode, activity.language].join('|')
-    if (lessonLanguageFor === key) return
-    lessonLanguageFor = key
-    if (ctx.value.entry !== 'problem' || teacherCollab.value) return
+    const lesson = [id, activity.day, activity.mode, activity.language].join('|')
    const item = lessonStore.find(id)
+    const key = [lesson, item?.draw && item.draw !== 'accepted' ? 'draw' : 'code'].join('|')
+    // 停在这道题上、只是课堂状态刷新了（比如刚画对图）：不跟着换，也不记，下回打开这道题再换
+    const stay = lessonViewing === lesson
+    lessonViewing = lesson
+    if (lessonSwitched.has(key) || stay) return
+    lessonSwitched.add(key)
+    if (ctx.value.entry !== 'problem' || teacherCollab.value) return
    if (!item) return
    if (item.draw && item.draw !== 'accepted') {
      if (problemStore.canDraw && codeStore.code.language !== 'Flowchart') problemStore.switchLanguage('Flowchart')
@@ -83,6 +83,8 @@ const doneBackground = computed(() => rgba(theme.value.successColor, 0.05))
  <div class="page oj-page">
    <div class="top">
      <h2>专题</h2>
+      <!-- 没有布置中的，就只有一组：数量写在标题旁边，不再另起一行「专题 14 个」把标题再说一遍 -->
+      <span v-if="!assigning.length && others.length" class="muted count">{{ others.length }} 个</span>
      <div class="spacer"></div>
      <n-input v-model:value="keyword" placeholder="搜专题" clearable class="search" />
      <!-- 手机上一行放不下，也没人在手机上出题，只给电脑 -->
@@ -133,8 +135,8 @@ const doneBackground = computed(() => rgba(theme.value.successColor, 0.05))
      </div>
    </template>

-    <div v-if="others.length" class="sect">
-      {{ assigning.length ? '其他专题' : '专题' }}
+    <div v-if="assigning.length && others.length" class="sect">
+      其他专题
      <span class="muted">{{ others.length }} 个</span>
    </div>
    <div class="small-grid">
@@ -191,6 +193,12 @@ const doneBackground = computed(() => rgba(theme.value.successColor, 0.05))
  font-size: var(--oj-fs-title);
 }

+/* 和分组标题旁的「N 个」同一档：小字、不加粗 */
+.top .count {
+  font-size: var(--oj-fs-sec);
+  font-weight: 400;
+}
+
 .search {
  width: 220px;
 }
@@ -122,8 +122,11 @@ onUnmounted(pause)
 */
 const editing = ref<false | 'edit' | 'new' | 'carry'>(false)

-/** 这节课做什么；推断出来的课为 null（代码交对或流程图画对都算） */
-const mode = computed(() => board.value?.mode ?? null)
+/**
+ * 第几道题今天做什么：今天几节里有这道题的要求合起来（先画流程图一节、再写代码一节 = 先画再写），
+ * 和学生那边的「做完」一致。推断出来的课为 null（代码交对或流程图画对都算）
+ */
+const modeAt = (index: number) => board.value?.problems[index]?.mode ?? null

 /**
 * 一个班一天可以上几节内容不同的课。打开任务页（或换到这个班）时，这一节已经布置了这么久，
@@ -200,7 +203,7 @@ function groupOf(student: TaskBoardStudent): Group {
  const cells = student.cells
  if (cells.length && cells.every((cell) => cell.status === 'accepted')) return 'done'
  if (!student.lastSubmitAt) return 'idle'
-  if (cells.some((cell) => isStuck(cell, mode.value))) return 'stuck'
+  if (cells.some((cell, i) => isStuck(cell, modeAt(i)))) return 'stuck'
  return 'working'
 }

@@ -327,23 +330,24 @@ function drawKind(cell: TaskBoardCell): ErrorKind {
 * 要画流程图的课，卡在画图上的按最后一张图归堆（drawKind）；先写了代码、没画图的单独一堆
 */
 function wrongOf(index: number): WrongPerson[] {
+  const mode = modeAt(index)
  return present.value.flatMap((student): WrongPerson[] => {
    const cell = student.cells[index]
    if (!cell || cell.status !== 'tried') return []
-    const stage = cellStage(cell, mode.value)
+    const stage = cellStage(cell, mode)
    if (stage === 'draw') {
      const latest = cell.flowchart?.latest
      const evaluated = !!latest && latest.status !== 0 && latest.status !== 1
      return [{ student, cell, kind: drawKind(cell), explain: evaluated ? 'draw' : null }]
    }
    if (stage === 'nodraw') return [{ student, cell, kind: { key: 'nodraw', label: '代码对了，还没画图', line: null }, explain: null }]
-    if (mode.value === 'both' && cell.flowchart?.status === 'accepted' && cell.codeStatus === 'none') {
+    if (mode === 'both' && cell.flowchart?.status === 'accepted' && cell.codeStatus === 'none') {
      return [{ student, cell, kind: { key: 'drawn', label: '图画对了，还没写代码', line: null }, explain: null }]
    }
    // 推断出来的课不分步：今天没代码、却画了流程图的单独一堆
    const kind: ErrorKind = cell.latest
      ? errorKind(cell.latest)
-      : !mode.value && cell.attempts
+      : !mode && cell.attempts
        ? { key: 'flowchart', label: '今天只画了流程图', line: null }
        : { key: 'before', label: '以前交过，今天还没交', line: null }
    return [{ student, cell, kind, explain: cell.latest ? 'code' : null }]
@@ -362,21 +366,18 @@ const problemStats = computed(() =>
    const challenged = problem.hasChallenges ? present.value.filter((student) => student.cells[i]?.challenge === 'done').length : null
    // 先画再写：两步各几人做到，老师一眼看出全班卡在画图还是写代码
    const steps =
-      mode.value === 'both'
+      problem.mode === 'both'
        ? {
            drawn: present.value.filter((student) => student.cells[i]?.flowchart?.status === 'accepted').length,
            coded: present.value.filter((student) => student.cells[i]?.codeStatus === 'accepted').length,
          }
        : null
-    return { problem, done, wrong, none: total - done - wrong, total, challenged, steps }
+    // 先画再写的题，没做完的里面有图画对了、还没写代码的，说「错着」不对 —— 改说「没做完」
+    const wrongWord = problem.mode === 'both' ? '没做完' : '错着'
+    return { problem, done, wrong, none: total - done - wrong, total, challenged, steps, wrongWord }
  }),
 )

-/**
- * 先画再写的课，没做完的里面有图画对了、还没写代码的，说「错着」不对 —— 改说「没做完」
- */
-const wrongWord = computed(() => (mode.value === 'both' ? '没做完' : '错着'))
-
 const selectedId = ref<number | null>(null)
 const selectedIndex = computed(() => (board.value?.problems ?? []).findIndex((problem) => problem.problemId === selectedId.value))
 function toggleProblem(problemId: number) {
@@ -408,10 +409,14 @@ const explainShow = ref(false)
 const explainIndex = ref(0)
 const explainProblemIndex = ref(-1)
 const explainProblem = computed(() => board.value?.problems[explainProblemIndex.value] ?? null)
-/** 弹层顶上那排人：这道题错着的人，顺序和错法堆一样 */
-const explainPeople = computed<ExplainPerson[]>(() => {
-  if (explainProblemIndex.value < 0) return []
-  const people = wrongOf(explainProblemIndex.value).filter((person) => person.explain)
+/**
+ * 弹层顶上那排人：这道题错着的人，顺序和错法堆一样。打开那一刻定下来，开着时不跟 15 秒的刷新变：
+ * 弹层记的是第几个人，名单一变（有人改对了、图评完了回到名单里）就成了讲着讲着换了个人
+ */
+const explainPeople = ref<ExplainPerson[]>([])
+function explainPeopleOf(problemIndex: number): ExplainPerson[] {
+  if (problemIndex < 0) return []
+  const people = wrongOf(problemIndex).filter((person) => person.explain)
  const order = new Map<string, number>()
  for (const person of people) {
    order.set(person.kind.key, (order.get(person.kind.key) ?? 0) + 1)
@@ -423,10 +428,11 @@ const explainPeople = computed<ExplainPerson[]>(() => {
        ? { userId: person.student.userId, username: person.student.username, flowchartId: person.cell.flowchart!.latest!.id, label: person.kind.label }
        : { userId: person.student.userId, username: person.student.username, submissionId: person.cell.latest!.submissionId, label: person.kind.label },
    )
-})
+}

 function openExplain(problemIndex: number, userId: number) {
  explainProblemIndex.value = problemIndex
+  explainPeople.value = explainPeopleOf(problemIndex)
  explainIndex.value = Math.max(
    0,
    explainPeople.value.findIndex((person) => person.userId === userId),
@@ -442,14 +448,15 @@ const cellColors = computed(() => ({
  actionColor: theme.value.actionColor,
  successColor: theme.value.successColor,
 }))
-const cellStyle = (cell: TaskBoardCell) => cellStyleOf(cell, board.value?.day, cellColors.value, mode.value)
-const cellTitle = (cell: TaskBoardCell, student: TaskBoardStudent) => cellTitleOf(cell, student, board.value?.day, mode.value)
-const cellText = (cell: TaskBoardCell) => cellTextOf(cell, mode.value)
+/** `index`：第几道题，格子按那道题今天做什么来画（modeAt） */
+const cellStyle = (cell: TaskBoardCell, index: number) => cellStyleOf(cell, board.value?.day, cellColors.value, modeAt(index))
+const cellTitle = (cell: TaskBoardCell, student: TaskBoardStudent, index: number) => cellTitleOf(cell, student, board.value?.day, modeAt(index))
+const cellText = (cell: TaskBoardCell, index: number) => cellTextOf(cell, modeAt(index))

 /** 点了能讲的格子：没做完，卡着的那一步有评完的图或今天的代码 */
-function explainable(cell: TaskBoardCell) {
+function explainable(cell: TaskBoardCell, index: number) {
  if (cell.status !== 'tried') return false
-  const stage = cellStage(cell, mode.value)
+  const stage = cellStage(cell, modeAt(index))
  if (stage === 'draw') {
    const latest = cell.flowchart?.latest
    return !!latest && latest.status !== 0 && latest.status !== 1
@@ -490,7 +497,7 @@ function submissionsHref(
  // SQL 题不受布置的语言限制，格子数的是 SQL 交的
  const language = problem?.isSql ? 'SQL' : board.value?.language
  // 只画流程图的课，格子数的全是流程图
-  const flowSide = flowchart || mode.value === 'flowchart'
+  const flowSide = flowchart || problem?.mode === 'flowchart'
  return router.resolve({
    name: 'submissions',
    query: {
@@ -532,7 +539,8 @@ function lastText(student: TaskBoardStudent) {
      />
      <div v-else-if="board?.problems.length && !needLesson" class="lesson">
        <span class="lesson-label">{{ board.source === 'teacher' ? '这节课' : '今天在做' }}</span>
-        <span v-if="board.mode && board.mode !== 'code'" class="chip lang">{{ LESSON_MODE_LABEL[board.mode] }}</span>
+        <!-- 写代码也写出来：只写「Python」的话，看不出这节是写代码还是先画再写 -->
+        <span v-if="board.mode" class="chip lang">{{ LESSON_MODE_LABEL[board.mode] }}</span>
        <span v-if="board.language" class="chip lang">{{ LANGUAGE_SHOW_VALUE[board.language] }}</span>
        <span v-for="problem in board.problems" :key="problem.problemId" class="chip">
          {{ problem.problemDisplayId }}
@@ -601,7 +609,7 @@ function lastText(student: TaskBoardStudent) {
            </span>
            <span v-if="stat.steps" class="card-steps">画对 {{ stat.steps.drawn }} · 写对 {{ stat.steps.coded }}</span>
            <span class="card-foot">
-              <span :class="stat.wrong ? 'wrong' : 'muted'">{{ wrongWord }} {{ stat.wrong }}</span>
+              <span :class="stat.wrong ? 'wrong' : 'muted'">{{ stat.wrongWord }} {{ stat.wrong }}</span>
              <span class="muted">没做 {{ stat.none }}</span>
              <span v-if="stat.challenged !== null" class="challenged"> 挑战成功 {{ stat.challenged }} </span>
            </span>
@@ -624,7 +632,7 @@ function lastText(student: TaskBoardStudent) {
              {{ board.problems[selectedIndex]!.title }}
            </a>
            <span>
-              {{ wrongWord }}的 <b class="wrong">{{ problemStats[selectedIndex]!.wrong }}</b> 人
+              {{ problemStats[selectedIndex]!.wrongWord }}的 <b class="wrong">{{ problemStats[selectedIndex]!.wrong }}</b> 人
            </span>
            <span class="muted">没做 {{ problemStats[selectedIndex]!.none }} 人</span>
            <div class="spacer"></div>
@@ -643,7 +651,7 @@ function lastText(student: TaskBoardStudent) {
                <template v-for="person in group.people" :key="person.student.userId">
                  <button v-if="person.explain" type="button" class="who" @click="openExplain(selectedIndex, person.student.userId)">
                    <UserName :username="person.student.username" />
-                    <span class="mini" :style="cellStyle(person.cell)">{{ cellText(person.cell) }}</span>
+                    <span class="mini" :style="cellStyle(person.cell, selectedIndex)">{{ cellText(person.cell, selectedIndex) }}</span>
                  </button>
                  <!-- 没有今天的代码可讲：去提交列表看他交过的 -->
                  <a
@@ -747,15 +755,15 @@ function lastText(student: TaskBoardStudent) {
                </td>
                <td v-for="(cell, i) in student.cells" :key="i" :class="{ hl: i === selectedIndex }">
                  <button
-                    v-if="explainable(cell)"
+                    v-if="explainable(cell, i)"
                    type="button"
                    class="cell"
                    :data-challenge="cell.challenge ?? undefined"
-                    :style="cellStyle(cell)"
-                    :title="cellTitle(cell, student)"
+                    :style="cellStyle(cell, i)"
+                    :title="cellTitle(cell, student, i)"
                    @click="openExplain(i, student.userId)"
                  >
-                    {{ cellText(cell) }}
+                    {{ cellText(cell, i) }}
                  </button>
                  <n-popover
                    v-else-if="cell.trail.length"
@@ -771,11 +779,11 @@ function lastText(student: TaskBoardStudent) {
                        class="cell"
                        :data-challenge="cell.challenge ?? undefined"
                        :class="{ picked: trailKey === `${student.userId}:${i}` }"
-                        :style="cellStyle(cell)"
-                        :title="cellTitle(cell, student)"
+                        :style="cellStyle(cell, i)"
+                        :title="cellTitle(cell, student, i)"
                        @click="toggleTrail(`${student.userId}:${i}`)"
                      >
-                        {{ cellText(cell) }}
+                        {{ cellText(cell, i) }}
                      </button>
                    </template>
                    <TrailPanel
@@ -791,15 +799,15 @@ function lastText(student: TaskBoardStudent) {
                    v-else-if="cell.attempts"
                    class="cell"
                    :data-challenge="cell.challenge ?? undefined"
-                    :style="cellStyle(cell)"
+                    :style="cellStyle(cell, i)"
                    :href="submissionsHref(student, board.problems[i], !cell.codeAttempts)"
                    target="_blank"
-                    :title="cellTitle(cell, student)"
+                    :title="cellTitle(cell, student, i)"
                  >
-                    {{ cellText(cell) }}
+                    {{ cellText(cell, i) }}
                  </a>
-                  <span v-else class="cell" :data-challenge="cell.challenge ?? undefined" :style="cellStyle(cell)" :title="cellTitle(cell, student)">
-                    {{ cellText(cell) }}
+                  <span v-else class="cell" :data-challenge="cell.challenge ?? undefined" :style="cellStyle(cell, i)" :title="cellTitle(cell, student, i)">
+                    {{ cellText(cell, i) }}
                  </span>
                </td>
                <td class="num">{{ doneCount(student) }}/{{ board.problems.length }}</td>
@@ -53,8 +53,8 @@ const envVersion = computed(() => {
 })

 // 一级路径就是菜单 key，对不上的页面（/user、/achievement 等）
-// 自然没有一项亮着。根路径没登录时就是题目列表，登录了是个人首页，不亮任何一项
-const active = computed(() => route.path.split('/')[1] || (userStore.isAuthed ? '' : 'problem'))
+// 自然没有一项亮着。根路径没登录时就是题目列表（亮「题目」），登录了是个人首页（亮「首页」）
+const active = computed(() => route.path.split('/')[1] || (userStore.isAuthed ? 'home' : 'problem'))

 async function handleLogout() {
  await userStore.signOut()
@@ -80,7 +80,8 @@ function renderIcon(icon: string) {
 * 顶栏导航的唯一一张表：桌面端渲染成一排纯文字，窄屏收进「菜单」下拉。
 * `key` 就是一级路径，用来判定高亮（见上面的 active）。
 *
- * 顺序是 自学 / 题目 / 提交 / 专题 / 比赛 / 排名 / 公告。「自学」进自学首页（/learn），
+ * 顺序是 首页 / 自学 / 题目 / 提交 / 专题 / 比赛 / 排名 / 公告。「首页」只给登录了的：没登录时根路径
+ * 就是题目列表，和「题目」是同一页（2026-11-03 用户要的，原来只能点左上角的站名回首页）。「自学」进自学首页（/learn），
 * 两门课、接着学哪一课都在那儿挑，不再是下拉。提交留在一级：学生天天回来看自己交的结果，老师课上翻全班代码也走它。
 * 公告 2026-10-13 回到顶栏（用户要的）：首页只放置顶那条了，别的公告得有个地方点得到。
 * 不用 n-menu：它横排每项固定占 100px，1280 宽的机房屏上会把顶栏挤成两行。
@@ -94,6 +95,7 @@ interface NavLink {

 const navLinks = computed<NavLink[]>(() =>
  [
+    { key: 'home', label: '首页', to: '/', show: userStore.isAuthed },
    { key: 'learn', label: '自学', to: '/learn' },
    { key: 'problem', label: '题目', to: '/problem' },
    { key: 'submission', label: '提交', to: '/submission', show: userStore.showSubmissions },
@@ -17,9 +17,12 @@ function names(list: Item[]) {
  return list.map((item) => `${item.problemDisplayId} ${item.title}`).join('、')
 }

-/** 「画流程图」「先画再写 · C语言」「C语言」：写代码是默认的，不写出来 */
-function languageText(value: LessonUpdate) {
-  const mode = value.mode && value.mode !== 'code' ? LESSON_MODE_LABEL[value.mode] : ''
+/**
+ * 「画流程图」「先画再写 · C语言」「C语言」。新布置的一节写代码是默认的，不写出来（前面配「用」）；
+ * 改了做法时 `spellCode` 把「写代码」也写出来 —— 从画流程图改成写 C，只说「C语言」学生看不出不用画了
+ */
+function languageText(value: LessonUpdate, spellCode = false) {
+  const mode = value.mode && (spellCode || value.mode !== 'code') ? LESSON_MODE_LABEL[value.mode] : ''
  return [mode, value.language ? LANGUAGE_SHOW_VALUE[value.language] : ''].filter(Boolean).join(' · ')
 }

@@ -44,8 +47,9 @@ const lines = computed(() => {
  if (value.added.length) result.push({ label: '加了', text: names(value.added) })
  if (value.removed.length) result.push({ label: '去掉了', text: names(value.removed) })
  if (value.languageChanged) {
-    const text = languageText(value)
-    result.push({ label: value.mode && value.mode !== 'code' ? '做法' : '语言', text: text ? `改成 ${text}` : value.mode === 'code' ? '改成写代码' : '不限了' })
+    // languageChanged 连做法一起算，分不出改的是哪样：一律写「做法」，连写代码带语言一起说
+    const text = languageText(value, true)
+    result.push({ label: '做法', text: text ? `改成 ${text}` : '不限了' })
  }
  if (value.reordered) result.push({ label: '', text: '换了题目的顺序' })
  return result
@@ -1,9 +1,22 @@
-import { LESSON_MODE_LABEL } from '@oj2/contract'
+import { LESSON_MODE_LABEL, type LessonMode } from '@oj2/contract'
 import { defineStore } from 'pinia'
 import { getClassActivity } from 'shared/api'
 import { LANGUAGE_SHOW_VALUE } from 'utils/constants'
 import type { ClassActivity, ClassActivityProblem } from 'utils/types'

+/**
+ * 学生这边这节课做什么：按每道题合起来的要求算（后端 todaySteps 把今天几节里同一道题的要求并在一起），
+ * 不直接用 `mode` —— 那是今天最后布置的那一节的。先布置画流程图、再「用这几道题写代码」，
+ * 最后一节是写代码，但还没画完的照样要画，标题只写「用 C语言做」就漏了画图。
+ * 推断出来的课为 null
+ */
+export function activityMode(activity: ClassActivity | null | undefined): LessonMode | null {
+  if (!activity?.mode) return null
+  const draw = activity.problems.some((item) => item.draw !== null)
+  const code = activity.problems.some((item) => item.code !== null)
+  return draw && code ? 'both' : draw ? 'flowchart' : code ? 'code' : activity.mode
+}
+
 /** 同一节课里来回换题不用每次都重拉；过了这么久再进题目页就重拉一次 */
 const STALE_MS = 2 * 60 * 1000

@@ -89,8 +102,8 @@ export const useLessonStore = defineStore('lesson', () => {
   * 以前布置的）为空。写代码是默认的，不写出来
   */
  const languageText = computed(() => {
-    const mode = activity.value?.mode
-    const language = activity.value?.language
+    const mode = activityMode(activity.value)
+    const language = mode === 'flowchart' ? null : activity.value?.language
    return [mode && mode !== 'code' ? LESSON_MODE_LABEL[mode] : '', language ? LANGUAGE_SHOW_VALUE[language] : ''].filter(Boolean).join(' · ')
  })

@@ -42,6 +42,11 @@ export const taskBoardProblemSchema = z.object({
  isSql: z.boolean(),
  /** 这道题配了挑战（见 problem.ts 的 challengeSchema）：题卡片写挑战成功几人 */
  hasChallenges: z.boolean(),
+  /**
+   * 这道题今天要做什么：这个班今天布置过的几节里有这道题的，要求合起来（先布置画流程图、再用同样的题
+   * 写代码 = both）。格子按它画，和学生那边的「做完」一致。推断出来的课为 null
+   */
+  mode: lessonModeSchema.nullable(),
 })

 export const taskBoardCellSchema = z.object({
Author	SHA1	Message	Date
xuyueandClaude Opus 5.5	41d2e46aa9	perf(排名): 打开排名页快一些，看「全服 · 全部」从 0.27 秒降到 0.08 秒 Deploy / deploy (push) Canceled after 0s Details 做对时刻在库里换成毫秒、按人聚成数组再取回，不再一行一个 timestamptz 逐条解析（全服全部历史六万多行，光解析就占 150ms）。名次与原来完全一致。 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-11-03 10:32:32 +08:00
xuyueandClaude Opus 5.5	f06bb063b4	feat(顶栏): 导航最左边加「首页」，和点站名一样回到首页没登录时不显示：那时首页就是题目列表，和「题目」是同一页。 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-11-03 09:36:41 +08:00
xuyueandClaude Opus 5.5	4a4cede99f	style(专题): 列表没有「布置中」时不再另起一行「专题 14 个」，数量写在标题旁边 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-11-03 09:34:59 +08:00
xuyueandClaude Opus 5.5	91057c1096	fix(课堂任务): 先画一节、再用这几道题写代码时，老师这边也认没画图的还没做完 - 任务页格子、老师首页「全做对」和每道题做对几人，按今天几节里同一道题合起来的要求算（和学生那边同一份口径，挪进 services/lesson.ts 的 todayNeeds）：写代码那节只交对了代码、没画图的，格子是「缺图」，不再打 ✓。后台和数据统计还是一节一行、各数各的 - 学生课堂条上「几人做对」也按合起来的要求数，不再把自己没做完的算进去 - 先画再写只交对了代码、图还没画的格子，不再挂挑战的圈 - 题目页标题下：流程图没画到 A 也写「流程图 C 级」（橙色），不再写「还没交过」 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-11-03 09:32:57 +08:00
xuyueandClaude Opus 5.5	c3f1413545	fix(课堂任务): 后台改一节不再把它排到同一分钟布置的另一节前面；学生管理员算进统计的课 - 后台「改」时刻只填到分，原来一保存就把布置时刻截成整分：先画流程图、紧接着再开一节写代码，只改了做什么，「今天最后一节」就换回了画流程图那节。没改时刻就留着原来的 - 数据统计「一行一节课」只数 Regular User，学生管理员的提交不算，和「做完 / 全班」的花名册对不上 - 学生「老师改了这节课」：画流程图改成写 C、先画再写改成写代码，原来写「语言改成 C语言」，看不出不用画了；现在写「做法改成写代码 · C语言」 - 学生课堂标题按每道题合起来的要求写：先画流程图、再用这几道题写代码时，不再只写「用 C语言做」 - 先画再写的题，切到别的题再回来不再被拽回画布（原来只记最后一道题） - 课堂任务顶上写代码的课也写「写代码」；讲错误的弹层开着时不再因为 15 秒刷新换了个人 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-11-03 09:26:39 +08:00
xuyueandClaude Opus 5.5	b09d479893	style(课堂任务): 后台列表分清写代码、先画再写、画流程图，能按做法筛原来写代码当默认值不写出来，只剩「C语言」「Python」，看着和别的分不开。现在三种都用不同颜色的标签写出来，筛选多一个「做什么」。 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>	2026-11-03 09:05:23 +08:00