feat(统计): 「今日统计」「数据统计」合成一个「统计」，打开是一行一节课，这节课在最上面

老师的提交列表上只剩一个「统计」按钮；什么都没筛时按课列（选「今天」就是原来今日统计看的），
点一行进那节课（班、题、时段都带好），左上「← 全部」回来；只填题号时仍按班级汇总，和题目页
统计页签对得上。数字行加结果条，统计里的「课堂看板」按钮去掉，改成有班正在上课时才引过去。
学生仍是「今日统计」。

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/oj/api.ts

@@ -40,6 +40,7 @@ import {
   type UserBadge,
   type FlowchartStatistics,
   type SubmissionStatistics,
+  type SubmissionLessons,
   type SubmissionStatisticsGrid,
   type TodaySubmissionStatistics,
 } from "@oj2/contract"
@@ -189,6 +190,13 @@ export function getSubmissionStatistics(
   })
 }
 
+/** 统计「一行一节课」的总览（没选班、没填学生和题号时）。limit 是列几节课，「再往前看」加它 */
+export function getSubmissionLessons(duration: { start?: string; end: string }, limit?: number) {
+  return api.get<SubmissionLessons>("submissions/statistics/lessons", {
+    params: { ...duration, limit },
+  })
+}
+
 /** 统计页的方块串：范围内每个学生的每一次提交（口径见契约 submissionStatisticsGridSchema） */
 export function getSubmissionStatisticsGrid(
   duration: { start?: string; end: string },

apps/web/src/oj/classroom/board.vue

@@ -269,7 +269,7 @@ function submissionsHref(
           >
         </n-text>
         <n-button :loading="loading" @click="load">刷新</n-button>
-        <!-- 看板只管今天；以前几节课的、任意时间段的去数据统计（带上这个班） -->
+        <!-- 看板只管今天；以前几节课的、任意时间段的去统计（带上这个班） -->
         <n-button
           v-if="!projector"
           @click="router.push({ name: 'statistics', query: className ? { className } : {} })"

apps/web/src/oj/problem/components/ProblemInfo.vue

@@ -15,7 +15,7 @@ import { useProblemPageContext } from "../composables/problemPageContext"
 /**
  * 「统计」页签（设计稿「题目页统计重设计」学生 A）。讲的是**这道题**：难不难 → 大家几次
  * 做对 → 常错在哪，全部按人算。学生多一行「你们班」、自己卡住了再多一张卡；老师多一张
- * 各班的表（只到班级这一层，不选班、不列人 —— 按人看是提交页「数据统计」的活）。
+ * 各班的表（只到班级这一层，不选班、不列人 —— 按人看是提交页「统计」的活）。
  * 原来的描述表、击败用户、饼图、历年 AC 率都去掉了。
  */
 const emit = defineEmits<{ openSubmissions: [] }>()
@@ -139,7 +139,7 @@ const hiddenClasses = computed(
   () => (stats.value?.classes?.length ?? 0) - shownClasses.value.length,
 )
 
-/** 点一个班、或者表下面那行：去提交页的「数据统计」按人看（新标签，题目页不动） */
+/** 点一个班、或者表下面那行：去「统计」按人看（新标签，题目页不动） */
 function openStatistics(className?: string) {
   const href = router.resolve({
     name: "statistics",
@@ -273,7 +273,7 @@ function segmentWidth(value: number, total: number) {
         </div>
       </div>
 
-      <!-- 老师：各班一行，和数据统计「按班级汇总」同一份数；按人看去那边 -->
+      <!-- 老师：各班一行，和统计「按班级汇总」同一份数；按人看去那边 -->
       <div v-if="stats.classes?.length" class="section">
         <b>各班做得怎样</b>
         <table class="classes">
@@ -292,7 +292,7 @@ function segmentWidth(value: number, total: number) {
               v-for="item in shownClasses"
               :key="item.className ?? ''"
               :class="{ pickable: item.className }"
-              :title="item.className ? '去数据统计看这个班的每个人' : undefined"
+              :title="item.className ? '新标签看这个班的每个人' : undefined"
               @click="item.className && openStatistics(item.className)"
             >
               <td>
@@ -332,7 +332,7 @@ function segmentWidth(value: number, total: number) {
           </a>
           <span class="spacer"></span>
           <a href="#" class="link small" @click.prevent="openStatistics()">
-            按人看谁没做对，去数据统计 <Icon icon="ph:arrow-square-out" :width="13" />
+            按人看谁没做对 <Icon icon="ph:arrow-square-out" :width="13" />
           </a>
         </div>
       </div>

apps/web/src/oj/statistics/components/Lessons.vue

@@ -0,0 +1,561 @@
+<script setup lang="ts">
+import { Icon } from "@iconify/vue"
+import { useThemeVars } from "naive-ui"
+import type { SubmissionLessons } from "@oj2/contract"
+import { parseTime, zonedParts } from "utils/functions"
+import { useTone } from "oj/submission/composables/tone"
+import { classLabel } from "oj/submission/utils"
+import { resultName, useResultColor } from "../results"
+
+type Lesson = SubmissionLessons["lessons"][number]
+
+/**
+ * 统计「一行一节课」的总览（设计稿「统计合二为一」B）。没选班、没填学生和题号时用它：
+ * 原来「今日统计」老师那一版（今天哪几个班上了课、几点到几点、错得最多的题）并进来，
+ * 换成任意时间段。按天分组，从近到远 —— 这节课在最上面；点一行进那节课（班、题、时段都带上）。
+ * 课怎么切的在后端（契约 submissionLessonsSchema）。
+ */
+const props = defineProps<{
+  data: SubmissionLessons
+  /** 时间段落在今天以内：每行多一根 7–20 点的横条（原来今日统计的时间轴） */
+  timeline: boolean
+  /** 「再往前看」在加载 */
+  loadingMore: boolean
+}>()
+const emit = defineEmits<{
+  pick: [lesson: Lesson]
+  /** 点「错得最多的题」里的一道：只看这道（按班级汇总） */
+  problem: [displayId: string]
+  more: []
+}>()
+
+const router = useRouter()
+const theme = useThemeVars()
+const tone = useTone()
+const resultColor = useResultColor()
+
+const WEEKDAYS = ["周日", "周一", "周二", "周三", "周四", "周五", "周六"]
+
+function dayText(day: string) {
+  const [y, m, d] = day.split("-").map(Number) as [number, number, number]
+  const weekday = WEEKDAYS[new Date(Date.UTC(y, m - 1, d)).getUTCDay()]
+  const today = parseTime(new Date(), "YYYY-MM-DD")
+  const yesterday = parseTime(new Date(Date.now() - 86_400_000), "YYYY-MM-DD")
+  const date = `${m}月${d}日 ${weekday}`
+  if (day === today) return `今天 · ${date}`
+  if (day === yesterday) return `昨天 · ${date}`
+  return y === Number(today.slice(0, 4)) ? date : `${y}年${date}`
+}
+
+/** 按天分组，天和天里的课都是从近到远，零散提交挂在对应那天下面 */
+const days = computed(() => {
+  const map = new Map<string, { lessons: Lesson[]; scattered: string }>()
+  for (const lesson of props.data.lessons) {
+    const entry = map.get(lesson.day) ?? { lessons: [], scattered: "" }
+    entry.lessons.push(lesson)
+    map.set(lesson.day, entry)
+  }
+  const scatteredByDay = new Map<string, string[]>()
+  for (const item of props.data.scattered) {
+    const name = item.className ? classLabel(item.className) : "没填班级的"
+    const text = `${name} ${item.userCount} 人 ${item.total} 次`
+    scatteredByDay.set(item.day, [...(scatteredByDay.get(item.day) ?? []), text])
+    if (!map.has(item.day)) map.set(item.day, { lessons: [], scattered: "" })
+  }
+  return [...map.entries()]
+    .sort((a, b) => b[0].localeCompare(a[0]))
+    .map(([day, entry]) => ({
+      day,
+      label: dayText(day),
+      // 最近的一节在最上面（用户说的）：打开就看到这节课，往下是更早的
+      lessons: [...entry.lessons].sort((a, b) => b.start.localeCompare(a.start)),
+      scattered: (scatteredByDay.get(day) ?? []).join(" · "),
+    }))
+})
+
+const lessonCount = computed(() => props.data.lessons.length)
+const liveLessons = computed(() => props.data.lessons.filter((lesson) => lesson.live))
+
+function clock(lesson: Lesson) {
+  return `${parseTime(lesson.start, "HH:mm")}–${parseTime(lesson.end, "HH:mm")}`
+}
+
+/** 23 人来了、花名册却只有 22（有个号不是学生角色）时，不写「23 / 22」 */
+function attendance(lesson: Lesson) {
+  return lesson.classSize >= lesson.userCount
+    ? `${lesson.userCount} / ${lesson.classSize} 人`
+    : `${lesson.userCount} 人`
+}
+
+function problemText(lesson: Lesson) {
+  return `${lesson.fromProblemSet ? "题单 " : ""}${lesson.problems.length} 道`
+}
+
+// ---------- 时间轴（只在今天以内） ----------
+
+function hourOf(value: string) {
+  const p = zonedParts(value)!
+  return p.hour + p.minute / 60
+}
+
+/** 横轴默认 7 点到 20 点（机房上课的时段），有更早更晚的课就往外扩 */
+const axis = computed(() => {
+  const list = props.data.lessons
+  const start = Math.min(7, ...list.map((item) => Math.floor(hourOf(item.start))))
+  const end = Math.max(20, ...list.map((item) => Math.ceil(hourOf(item.end))))
+  const ticks = []
+  for (let hour = start + (start % 2); hour <= end; hour += 2) ticks.push(hour)
+  return { start, end, ticks }
+})
+
+function axisLeft(hour: number) {
+  const { start, end } = axis.value
+  return `${((hour - start) / (end - start)) * 100}%`
+}
+
+function barStyle(lesson: Lesson) {
+  const from = hourOf(lesson.start)
+  const to = hourOf(lesson.end)
+  const { start, end } = axis.value
+  return {
+    left: axisLeft(from),
+    width: `max(6px, ${((to - from) / (end - start)) * 100}%)`,
+    background: lesson.live ? theme.value.successColor : "#3f5f87",
+  }
+}
+
+const nowHour = computed(() => {
+  const hour = hourOf(new Date().toISOString())
+  return hour >= axis.value.start && hour <= axis.value.end ? hour : null
+})
+
+function percent(value: number, total: number) {
+  return total ? `${(value / total) * 100}%` : "0"
+}
+</script>
+
+<template>
+  <div class="lessons">
+    <div
+      v-if="liveLessons.length"
+      class="live"
+      :style="{ background: tone('success').background, color: tone('success').color }"
+    >
+      <span>{{ liveLessons.map((item) => classLabel(item.className)).join("、") }}正在上课</span>
+      <span class="spacer"></span>
+      <a href="#" class="live-link" @click.prevent="router.push('/classroom')">
+        <Icon icon="ph:monitor" :width="14" />去课堂看板
+      </a>
+    </div>
+
+    <div v-if="!lessonCount && !data.scattered.length" class="empty">这段时间没有人交</div>
+    <div v-else-if="!lessonCount" class="note">
+      这段时间没有哪个班一起上课（同一个班 5 人以上做同一道题才算一节课），只有零散提交
+    </div>
+
+    <template v-for="group in days" :key="group.day">
+      <div class="day">{{ group.label }}</div>
+      <a
+        v-for="lesson in group.lessons"
+        :key="lesson.className + lesson.start"
+        href="#"
+        class="row"
+        @click.prevent="emit('pick', lesson)"
+      >
+        <span class="c-time">{{ clock(lesson) }}</span>
+        <span v-if="timeline" class="c-axis">
+          <span
+            v-for="tick in axis.ticks"
+            :key="tick"
+            class="grid"
+            :style="{ left: axisLeft(tick) }"
+          ></span>
+          <span class="bar" :style="barStyle(lesson)"></span>
+          <span v-if="nowHour !== null" class="now" :style="{ left: axisLeft(nowHour) }"></span>
+        </span>
+        <b class="c-class">{{ classLabel(lesson.className) }}</b>
+        <span class="c-came">{{ attendance(lesson) }}</span>
+        <span class="c-probs">{{ problemText(lesson) }}</span>
+        <span class="c-rate">
+          {{ lesson.total }} 次 ·
+          {{ lesson.live ? "上课中" : `正确率 ${Math.round(lesson.correctRate)}%` }}
+        </span>
+        <span class="c-hard">
+          <template v-if="lesson.hardest">
+            <n-text depth="3">错得最多</n-text>
+            <n-text depth="3" class="pid">{{ lesson.hardest.problemDisplayId }}</n-text>
+            {{ lesson.hardest.problemTitle }}
+            <span :style="{ color: tone('warning').color }"
+              >· 没过 {{ lesson.hardest.failed }} 次</span
+            >
+          </template>
+        </span>
+        <span class="c-go">看这节课<Icon icon="ph:caret-right-bold" :width="12" /></span>
+      </a>
+      <div v-if="group.scattered" class="scattered">
+        {{ group.lessons.length ? "另有零散提交：" : "零散提交：" }}{{ group.scattered }}
+      </div>
+    </template>
+
+    <div v-if="timeline && lessonCount" class="axis-row">
+      <span class="c-time"></span>
+      <span class="c-axis axis">
+        <!-- 挨着「现在」的刻度不写，不然两个字叠在一起 -->
+        <template v-for="tick in axis.ticks" :key="tick">
+          <span
+            v-if="nowHour === null || Math.abs(tick - nowHour) > 0.8"
+            :style="{ left: axisLeft(tick) }"
+          >
+            {{ tick }}
+          </span>
+        </template>
+        <span v-if="nowHour !== null" class="now-label" :style="{ left: axisLeft(nowHour) }">
+          现在
+        </span>
+      </span>
+    </div>
+
+    <div v-if="data.hasMore" class="more">
+      <n-button size="small" :loading="loadingMore" @click="emit('more')">
+        更早的课（现在列了最近 {{ lessonCount }} 节）
+      </n-button>
+    </div>
+
+    <template v-if="data.hardProblems.length">
+      <div class="section-title">
+        <b>错得最多的题</b>
+        <n-text depth="3" class="small">按没过的次数 · 点题目看各班做得怎样</n-text>
+      </div>
+      <table class="hard">
+        <thead>
+          <tr>
+            <th>题目</th>
+            <th>哪个班</th>
+            <th>提交</th>
+            <th>没过的原因</th>
+            <th class="right">做对</th>
+          </tr>
+        </thead>
+        <tbody>
+          <tr v-for="item in data.hardProblems" :key="item.problemDisplayId">
+            <td class="hard-title">
+              <a href="#" @click.prevent="emit('problem', item.problemDisplayId)">
+                <n-text depth="3">{{ item.problemDisplayId }}</n-text> {{ item.problemTitle }}
+              </a>
+            </td>
+            <td>
+              <n-text depth="2">{{ item.className ? classLabel(item.className) : "—" }}</n-text>
+            </td>
+            <td>{{ item.total }} 次</td>
+            <td>
+              <span class="mini">
+                <span
+                  :style="{ width: percent(item.accepted, item.total), background: resultColor(0) }"
+                ></span>
+                <span
+                  v-for="fail in item.failures"
+                  :key="fail.result"
+                  :style="{
+                    width: percent(fail.count, item.total),
+                    background: resultColor(fail.result),
+                  }"
+                ></span>
+              </span>
+              <n-text v-if="item.failures[0]" depth="2" class="small">
+                {{ resultName(item.failures[0].result) }} {{ item.failures[0].count }}
+              </n-text>
+            </td>
+            <td
+              class="right"
+              :style="{
+                color: item.acceptedUsers < item.userCount ? tone('error').color : undefined,
+                fontWeight: item.acceptedUsers < item.userCount ? 600 : undefined,
+              }"
+            >
+              {{ item.acceptedUsers }} / {{ item.userCount }} 人
+            </td>
+          </tr>
+        </tbody>
+      </table>
+    </template>
+  </div>
+</template>
+
+<style scoped>
+.lessons {
+  flex: 1;
+  min-height: 0;
+  overflow: auto;
+  padding-bottom: 20px;
+  font-size: 14px;
+}
+
+.live {
+  display: flex;
+  align-items: center;
+  margin: 12px 20px 4px;
+  padding: 8px 14px;
+  border-radius: 8px;
+}
+
+.live-link {
+  color: inherit;
+  font-weight: 600;
+  text-decoration: none;
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+}
+
+.spacer {
+  flex: 1 1 0;
+}
+
+.empty {
+  padding: 48px 0;
+  text-align: center;
+  color: v-bind("theme.textColor3");
+}
+
+.note {
+  padding: 16px 20px 4px;
+  font-size: 13px;
+  color: v-bind("theme.textColor3");
+}
+
+.day {
+  position: sticky;
+  top: 0;
+  z-index: 1;
+  height: 28px;
+  display: flex;
+  align-items: center;
+  padding: 0 20px;
+  font-size: 12px;
+  font-weight: 600;
+  color: v-bind("theme.textColor3");
+  background: v-bind("theme.actionColor");
+  border-bottom: 1px solid v-bind("theme.dividerColor");
+}
+
+.row {
+  height: 44px;
+  display: flex;
+  align-items: center;
+  padding: 0 20px;
+  border-bottom: 1px solid v-bind("theme.dividerColor");
+  color: v-bind("theme.textColor1");
+  text-decoration: none;
+  white-space: nowrap;
+}
+
+.row:hover {
+  background: v-bind("theme.hoverColor");
+}
+
+.c-time {
+  width: 110px;
+  flex: none;
+  color: v-bind("theme.textColor2");
+  font-variant-numeric: tabular-nums;
+}
+
+.c-axis {
+  position: relative;
+  width: 200px;
+  height: 28px;
+  flex: none;
+  margin-right: 20px;
+}
+
+.c-class {
+  width: 120px;
+  flex: none;
+}
+
+.c-came,
+.c-probs {
+  width: 96px;
+  flex: none;
+  color: v-bind("theme.textColor2");
+}
+
+.c-rate {
+  width: 170px;
+  flex: none;
+  color: v-bind("theme.textColor2");
+}
+
+.c-hard {
+  flex: 1;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  font-size: 13px;
+}
+
+.pid {
+  margin-left: 10px;
+}
+
+.c-go {
+  flex: none;
+  margin-left: 12px;
+  display: inline-flex;
+  align-items: center;
+  gap: 2px;
+  font-size: 13px;
+  color: v-bind("theme.primaryColor");
+}
+
+.grid {
+  position: absolute;
+  top: 4px;
+  bottom: 4px;
+  width: 1px;
+  background: v-bind("theme.dividerColor");
+}
+
+.bar {
+  position: absolute;
+  top: 50%;
+  height: 12px;
+  margin-top: -6px;
+  border-radius: 3px;
+}
+
+.now {
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  width: 2px;
+  background: v-bind("theme.successColor");
+}
+
+.axis-row {
+  display: flex;
+  padding: 0 20px;
+  height: 20px;
+}
+
+.axis-row .c-axis {
+  height: 20px;
+}
+
+.axis span {
+  position: absolute;
+  top: 3px;
+  transform: translateX(-50%);
+  white-space: nowrap;
+  font-size: 11px;
+  color: v-bind("theme.textColor3");
+}
+
+.axis .now-label {
+  font-weight: 600;
+  color: v-bind("theme.successColor");
+  background: v-bind("theme.cardColor");
+  padding: 0 2px;
+}
+
+.scattered {
+  padding: 7px 20px;
+  font-size: 12px;
+  color: v-bind("theme.textColor3");
+  border-bottom: 1px solid v-bind("theme.dividerColor");
+}
+
+.more {
+  padding: 12px 20px 0;
+}
+
+.section-title {
+  display: flex;
+  align-items: baseline;
+  gap: 10px;
+  padding: 18px 20px 6px;
+}
+
+.small {
+  font-size: 13px;
+}
+
+.hard {
+  width: calc(100% - 40px);
+  margin: 0 20px;
+  border-collapse: collapse;
+  font-size: 13px;
+}
+
+.hard th {
+  text-align: left;
+  font-weight: normal;
+  color: v-bind("theme.textColor3");
+  padding: 4px 8px 6px 0;
+  border-bottom: 1px solid v-bind("theme.dividerColor");
+}
+
+.hard td {
+  padding: 8px 8px 8px 0;
+  border-bottom: 1px solid v-bind("theme.dividerColor");
+  white-space: nowrap;
+}
+
+.hard .right {
+  text-align: right;
+  padding-right: 0;
+}
+
+.hard-title a {
+  color: v-bind("theme.textColor1");
+  text-decoration: none;
+}
+
+.hard-title a:hover {
+  color: v-bind("theme.primaryColor");
+}
+
+.mini {
+  display: inline-flex;
+  width: 70px;
+  height: 8px;
+  border-radius: 2px;
+  overflow: hidden;
+  gap: 1px;
+  margin-right: 8px;
+  vertical-align: middle;
+}
+
+/* 1366 以下（机房 1280）：横条窄一点，给「错得最多」留地方 */
+@media (max-width: 1365px) {
+  .c-axis {
+    width: 150px;
+    margin-right: 14px;
+  }
+  .c-rate {
+    width: 150px;
+  }
+}
+
+/* 手机：老师很少在手机上看统计，只保证不坏 —— 一行折成两行 */
+@media (max-width: 767px) {
+  .row {
+    height: auto;
+    flex-wrap: wrap;
+    row-gap: 4px;
+    padding: 8px 14px;
+    white-space: normal;
+  }
+  .c-axis,
+  .axis-row {
+    display: none;
+  }
+  .c-hard {
+    flex-basis: 100%;
+  }
+  .hard {
+    display: block;
+    overflow-x: auto;
+  }
+}
+</style>

apps/web/src/oj/statistics/components/StatisticsView.vue

@@ -3,11 +3,13 @@ import { Icon } from "@iconify/vue"
 import { useThemeVars } from "naive-ui"
 import type {
   FlowchartStatistics,
+  SubmissionLessons,
   SubmissionStatistics,
   SubmissionStatisticsGrid,
 } from "@oj2/contract"
 import {
   getFlowchartStatistics,
+  getSubmissionLessons,
   getSubmissionStatistics,
   getSubmissionStatisticsGrid,
 } from "oj/api"
@@ -16,15 +18,24 @@ import { fromPickerValue, toPickerValue } from "utils/functions"
 import { useTone } from "oj/submission/composables/tone"
 import { classLabel } from "oj/submission/utils"
 import { DEFAULT_PERIOD, PERIOD_OPTIONS, periodRange, type Period } from "../period"
+import { resultName, useResultColor } from "../results"
 import ByClass from "./ByClass.vue"
 import CodeStats from "./CodeStats.vue"
+import Lessons from "./Lessons.vue"
 import RingChart from "./RingChart.vue"
 import StatItem from "./StatItem.vue"
 
 /**
- * 数据统计的主体（设计稿「统计重设计 · 定稿 B」）。两处用它：提交列表里的弹框（老师
- * 平时从这里看），和 /statistics 页面（课堂看板「回头看」、题目页、今日统计之类从别处
- * 进来的，条件放在地址栏里能刷新、能转发）。
+ * 统计的主体（设计稿「统计重设计 · 定稿 B」+「统计合二为一」B）。两处用它：提交列表里的弹框
+ * （老师平时从这里看），和 /statistics 页面（课堂看板「回头看」、题目页之类从别处进来的，
+ * 条件放在地址栏里能刷新、能转发）。
+ *
+ * 代码页签按条件分三种看法：
+ * - 什么都没填：**一行一节课**（Lessons）。原来「今日统计」老师那一版并进来了，选「今天」
+ *   就是它，选别的时间段也一样有
+ * - 只填了题号：**按班级汇总**（ByClass）—— 题目页统计页签点进来就是这种，口径和那边的各班表一致
+ * - 选了班或填了学生：左边题目、右边学生（CodeStats）
+ * 从前两种点进去时左上角有「← 全部」回来。
  *
  * 分工：**课堂看板管这节课，这里管回头看**（用户定的）。所以不自动刷新、没有
  * 投影用的大字名单和请假隐藏 —— 那些在看板上。课堂统计一般看一两节课，时间段默认「一节课」。
@@ -44,10 +55,10 @@ const emit = defineEmits<{
   list: [query: Record<string, string>]
 }>()
 
-const router = useRouter()
 const configStore = useConfigStore()
 const theme = useThemeVars()
 const tone = useTone()
+const resultColor = useResultColor()
 
 const tab = defineModel<string>("tab", { default: "code" })
 const className = defineModel<string>("className", { default: "" })
@@ -57,12 +68,6 @@ const period = defineModel<string>("period", { default: DEFAULT_PERIOD })
 const from = defineModel<string>("from", { default: "" })
 const to = defineModel<string>("to", { default: "" })
 
-const periodValue = computed<Period>(() =>
-  PERIOD_OPTIONS.some((option) => option.value === period.value)
-    ? (period.value as Period)
-    : DEFAULT_PERIOD,
-)
-
 /** 地址栏里的 from / to 是手改过、不是数字的话当没选（不然 toISOString 抛错整页空白） */
 const custom = computed<[number, number] | null>(() => {
   const a = Number(from.value)
@@ -70,6 +75,20 @@ const custom = computed<[number, number] | null>(() => {
   return from.value && to.value && Number.isFinite(a) && Number.isFinite(b) ? [a, b] : null
 })
 
+const periodValue = computed<Period>(() => {
+  // 「那节课」要带着精确的起止时刻，地址栏里缺了就退回默认
+  if (period.value === "lesson") return custom.value ? "lesson" : DEFAULT_PERIOD
+  return PERIOD_OPTIONS.some((option) => option.value === period.value)
+    ? (period.value as Period)
+    : DEFAULT_PERIOD
+})
+
+/** 从「一行一节课」点进某一节课时，下拉里临时多一项「那节课」 */
+const periodOptions = computed(() => [
+  ...(periodValue.value === "lesson" ? [{ label: "那节课", value: "lesson" }] : []),
+  ...PERIOD_OPTIONS.map((o) => ({ label: o.label, value: o.value as string })),
+])
+
 /** n-date-picker 按浏览器时区渲染，存取都要平移到东八区（见 utils/functions 的注释） */
 const pickerValue = computed<[number, number] | null>(() =>
   custom.value ? [toPickerValue(custom.value[0]), toPickerValue(custom.value[1])] : null,
@@ -99,14 +118,31 @@ const loading = ref(false)
 const failed = ref("")
 const stats = ref<SubmissionStatistics | null>(null)
 const grid = ref<SubmissionStatisticsGrid | null>(null)
+const lessons = ref<SubmissionLessons | null>(null)
 const flow = ref<FlowchartStatistics | null>(null)
 
+type Mode = "lessons" | "byClass" | "people"
+/** 三种看法，见顶上的注释 */
+const mode = computed<Mode>(() =>
+  className.value || studentParam.value ? "people" : problem.value.trim() ? "byClass" : "lessons",
+)
+
+/** 一次列几节课，「更早的课」每点一次多 50 节 */
+const LESSON_PAGE = 50
+const lessonLimit = ref(LESSON_PAGE)
+const loadingMore = ref(false)
+
 /**
  * 这一份数据是按什么条件查出来的。页面上的标签（按班级汇总还是看人、「做完」还是
  * 「做对过题」、时间范围那句话）跟着它走，不跟着输入框 —— 老师边打字边看时，数据还是
  * 上一次的，标签先变了就对不上
  */
-const shown = ref({ byClass: true, explicit: false, rangeText: "", withinToday: false })
+const shown = ref<{ mode: Mode; explicit: boolean; rangeText: string; withinToday: boolean }>({
+  mode: "lessons",
+  explicit: false,
+  rangeText: "",
+  withinToday: false,
+})
 let seq = 0
 
 const ERROR_TEXT: Record<string, string> = {
@@ -119,7 +155,7 @@ async function load() {
   const range = periodRange(periodValue.value, custom.value)
   const duration = { start: range.start, end: range.end }
   const snapshot = {
-    byClass: !studentParam.value && !className.value,
+    mode: mode.value,
     explicit: !!problem.value.trim(),
     rangeText: range.text,
     withinToday: range.withinToday,
@@ -136,6 +172,16 @@ async function load() {
       )
       if (current !== seq) return
       flow.value = res
+    } else if (snapshot.mode === "lessons") {
+      // 一行一节课不要方块串：那个接口最多 5000 条，课在后端切
+      lessonLimit.value = LESSON_PAGE
+      const [s, l] = await Promise.all([
+        getSubmissionStatistics(duration, problem.value, studentParam.value, className.value),
+        getSubmissionLessons(duration, lessonLimit.value),
+      ])
+      if (current !== seq) return
+      stats.value = s
+      lessons.value = l
     } else {
       const [s, g] = await Promise.all([
         getSubmissionStatistics(duration, problem.value, studentParam.value, className.value),
@@ -151,6 +197,7 @@ async function load() {
     // 失败了就别留着上一次的结果配这一次的条件 —— 清掉，说清楚为什么
     stats.value = null
     grid.value = null
+    lessons.value = null
     flow.value = null
     const code = (error as { error?: string })?.error ?? ""
     failed.value = ERROR_TEXT[code] ?? "没拉下来，改一下条件再试"
@@ -159,6 +206,26 @@ async function load() {
   }
 }
 
+/** 「更早的课」：只重拉课那一份，数字行不动 */
+async function loadMore() {
+  const current = seq
+  loadingMore.value = true
+  try {
+    const range = periodRange(periodValue.value, custom.value)
+    const next = await getSubmissionLessons(
+      { start: range.start, end: range.end },
+      lessonLimit.value + LESSON_PAGE,
+    )
+    if (current !== seq) return
+    lessonLimit.value += LESSON_PAGE
+    lessons.value = next
+  } catch {
+    if (current === seq) failed.value = "更早的课没拉下来，再点一次试试"
+  } finally {
+    loadingMore.value = false
+  }
+}
+
 onMounted(load)
 watch([tab, className, periodValue, custom], load)
 watchDebounced([username, problem], load, { debounce: 600, maxWait: 1500 })
@@ -176,11 +243,13 @@ const judged = computed(() =>
   stats.value ? stats.value.submissionCount - stats.value.judgingCount : 0,
 )
 
-// ---------- 两个入口 ----------
+// ---------- 右上角的入口 ----------
 
 /**
- * 1366 以下（机房 1280 的屏）右上两个入口只留图标。弹框比屏幕窄一圈、还多一个关闭，
- * 1366 的屏上整排放不下，所以弹框里宽一档才出字
+ * 1366 以下（机房 1280 的屏）「在提交列表里看」只留图标。弹框比屏幕窄一圈、还多一个关闭，
+ * 1366 的屏上整排放不下，所以弹框里宽一档才出字。
+ * 原来旁边还有一个「这节课去课堂看板」：顶栏已经有看板，统计里再放一个成了干扰项（用户说的），
+ * 现在只在有班正在上课时，在课的列表上方引过去
  */
 const narrow = useMediaQuery(props.modal ? "(max-width: 1439px)" : "(max-width: 1365px)")
 
@@ -194,16 +263,79 @@ function openList() {
   })
 }
 
+// ---------- 点进去 / 回来 ----------
+
+type Snapshot = Record<"className" | "username" | "problem" | "period" | "from" | "to", string>
+/** 从「一行一节课」或「按班级汇总」点进去之前的条件，「← 全部」拿它回去 */
+const backTo = ref<Snapshot | null>(null)
+
+function remember() {
+  backTo.value = {
+    className: className.value,
+    username: username.value,
+    problem: problem.value,
+    period: period.value,
+    from: from.value,
+    to: to.value,
+  }
+}
+
+function goBack() {
+  const snap = backTo.value
+  if (!snap) return
+  backTo.value = null
+  className.value = snap.className
+  username.value = snap.username
+  problem.value = snap.problem
+  period.value = snap.period
+  from.value = snap.from
+  to.value = snap.to
+}
+
+// 自己把条件清回了总览，就不用再显示「← 全部」
+watch(mode, (value) => {
+  if (value === "lessons") backTo.value = null
+})
+
 function pickClass(value: string) {
+  remember()
   className.value = value
   username.value = ""
 }
+
+/** 点一节课：这个班、这节课的题、这节课第一条到最后一条（多留 1 秒：库里存到微秒，转成毫秒会截掉零头） */
+function pickLesson(lesson: SubmissionLessons["lessons"][number]) {
+  remember()
+  className.value = lesson.className
+  username.value = ""
+  problem.value = lesson.problems.join(" ")
+  from.value = String(Date.parse(lesson.start))
+  to.value = String(Date.parse(lesson.end) + 1000)
+  period.value = "lesson"
+}
+
+/** 点「错得最多的题」里的一道：只看这道，按班级汇总 */
+function pickProblem(displayId: string) {
+  remember()
+  problem.value = displayId
+}
+
+// ---------- 数字行的结果条 ----------
+
+const results = computed(() => stats.value?.results ?? [])
+function resultWidth(value: number) {
+  const total = stats.value?.submissionCount ?? 0
+  return total ? `${(value / total) * 100}%` : "0"
+}
 </script>
 
 <template>
   <div class="stats" :class="{ modal }">
     <div class="filters">
-      <span class="title">数据统计</span>
+      <span class="title">统计</span>
+      <button v-if="backTo" type="button" class="back" title="回到点进来之前" @click="goBack">
+        <Icon icon="ph:caret-left-bold" :width="13" />全部
+      </button>
       <n-radio-group v-model:value="tab" size="small">
         <n-radio-button value="code">代码</n-radio-button>
         <n-radio-button value="flow">流程图</n-radio-button>
@@ -235,7 +367,7 @@ function pickClass(value: string) {
         :value="periodValue"
         class="w-period"
         size="small"
-        :options="PERIOD_OPTIONS.map((o) => ({ label: o.label, value: o.value }))"
+        :options="periodOptions"
         :consistent-menu-width="false"
         @update:value="(v: string) => (period = v)"
       />
@@ -255,16 +387,6 @@ function pickClass(value: string) {
         >选一下开始和结束的日子，没选先按今天算</span
       >
       <span class="spacer"></span>
-      <n-button
-        size="small"
-        quaternary
-        title="这节课去课堂看板"
-        aria-label="这节课去课堂看板"
-        @click="router.push('/classroom')"
-      >
-        <template #icon><Icon icon="ph:monitor" /></template>
-        <template v-if="!narrow">这节课去课堂看板</template>
-      </n-button>
       <n-button size="small" title="在提交列表里看" aria-label="在提交列表里看" @click="openList">
         <template #icon><Icon icon="ph:arrow-square-out" /></template>
         <template v-if="!narrow">在提交列表里看</template>
@@ -278,7 +400,7 @@ function pickClass(value: string) {
       <FlowStats v-if="flow" :data="flow" />
     </template>
 
-    <template v-else-if="stats && grid">
+    <template v-else-if="stats && (shown.mode === 'lessons' ? lessons : grid)">
       <div class="summary">
         <StatItem label="提交" :value="stats.submissionCount" unit="条" />
         <StatItem
@@ -286,6 +408,14 @@ function pickClass(value: string) {
           :value="stats.submissionCount ? `${Math.round(stats.correctRate)}%` : '—'"
           :unit="stats.judgingCount ? `判题中 ${stats.judgingCount}` : ''"
         />
+        <template v-if="shown.mode === 'lessons' && lessons">
+          <StatItem label="交过的人" :value="stats.data.length" unit="人" />
+          <StatItem
+            label="上了几节课"
+            :value="`${lessons.lessons.length}${lessons.hasMore ? '+' : ''}`"
+            unit="节"
+          />
+        </template>
         <template v-if="personCount">
           <StatItem
             :label="hasProblems ? '做完' : '做对过题'"
@@ -307,6 +437,22 @@ function pickClass(value: string) {
           tone="warning"
         />
         <span class="spacer"></span>
+        <div v-if="results.length" class="result-bar">
+          <div class="result-track">
+            <span
+              v-for="item in results"
+              :key="item.result"
+              :style="{ width: resultWidth(item.count), background: resultColor(item.result) }"
+              :title="`${resultName(item.result)} ${item.count}`"
+            ></span>
+          </div>
+          <div class="result-legend">
+            <span v-for="item in results.slice(0, 3)" :key="item.result">
+              <i :style="{ background: resultColor(item.result) }"></i>{{ resultName(item.result) }}
+              <b>{{ item.count }}</b>
+            </span>
+          </div>
+        </div>
         <span class="ring-wrap">
           <RingChart
             :value="stats.acceptedCount"
@@ -326,8 +472,22 @@ function pickClass(value: string) {
           <span class="ring-label">班级<br />完成度</span>
         </span>
       </div>
-      <ByClass v-if="shown.byClass" :grid="grid" :explicit="shown.explicit" @pick="pickClass" />
-      <CodeStats v-else :stats="stats" :grid="grid" :explicit="shown.explicit" />
+      <Lessons
+        v-if="shown.mode === 'lessons' && lessons"
+        :data="lessons"
+        :timeline="shown.withinToday"
+        :loading-more="loadingMore"
+        @pick="pickLesson"
+        @problem="pickProblem"
+        @more="loadMore"
+      />
+      <ByClass
+        v-else-if="shown.mode === 'byClass' && grid"
+        :grid="grid"
+        :explicit="shown.explicit"
+        @pick="pickClass"
+      />
+      <CodeStats v-else-if="grid" :stats="stats" :grid="grid" :explicit="shown.explicit" />
     </template>
   </div>
 </template>
@@ -369,6 +529,56 @@ function pickClass(value: string) {
   margin-right: 6px;
 }
 
+.back {
+  height: 28px;
+  padding: 0 10px 0 6px;
+  border: 0;
+  border-radius: 4px;
+  font: inherit;
+  font-size: 13px;
+  display: inline-flex;
+  align-items: center;
+  gap: 2px;
+  cursor: pointer;
+  color: v-bind("theme.textColor2");
+  background: v-bind("theme.actionColor");
+}
+
+.back:hover {
+  color: v-bind("theme.primaryColor");
+}
+
+.result-bar {
+  min-width: 220px;
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.result-track {
+  display: flex;
+  height: 8px;
+  border-radius: 3px;
+  overflow: hidden;
+  gap: 1px;
+}
+
+.result-legend {
+  display: flex;
+  gap: 10px;
+  font-size: 12px;
+  white-space: nowrap;
+  color: v-bind("theme.textColor2");
+}
+
+.result-legend i {
+  display: inline-block;
+  width: 8px;
+  height: 8px;
+  border-radius: 2px;
+  margin-right: 4px;
+}
+
 .vsep {
   width: 1px;
   height: 20px;

apps/web/src/oj/statistics/index.vue

@@ -4,7 +4,7 @@ import StatisticsView from "./components/StatisticsView.vue"
 import { DEFAULT_PERIOD } from "./period"
 
 /**
- * 数据统计的页面形态：课堂看板「回头看」、题目页统计页签、今日统计从别处进来时用。
+ * 统计的页面形态：课堂看板「回头看」、题目页统计页签这些从别处进来时用。
  * 提交列表里是弹框（用户定的），两边是同一个 StatisticsView。
  *
  * 查询条件都在地址栏里：带过来、刷新、转发给别的老师都还是这一份。

apps/web/src/oj/statistics/period.ts

@@ -22,7 +22,11 @@ export const PERIOD_OPTIONS = [
   { label: "自己选日子", value: "custom" },
 ] as const
 
-export type Period = (typeof PERIOD_OPTIONS)[number]["value"]
+/**
+ * `lesson`：从「一行一节课」点进某一节课，from / to 是那节课第一条、最后一条提交的时刻
+ * （精确到毫秒，不是「自己选日子」那种按天）。它不在下拉里 —— 选中时下拉临时多出一项「那节课」
+ */
+export type Period = (typeof PERIOD_OPTIONS)[number]["value"] | "lesson"
 export const DEFAULT_PERIOD: Period = "1h"
 
 /** 东八区某天 0 点对应的 UTC 时刻 */
@@ -74,6 +78,14 @@ export function periodRange(period: Period, custom: [number, number] | null, now
     case "term":
       start = termStart(now)
       break
+    case "lesson":
+      if (custom) {
+        start = custom[0]
+        end = custom[1]
+      } else {
+        start = now - HOUR
+      }
+      break
     case "custom":
       if (custom) {
         start = custom[0]
@@ -100,6 +112,9 @@ function describe(start: number | null, end: number, period: Period) {
   if (period === "1h" || period === "2h") {
     return `${parseTime(new Date(start), "HH:mm")}–${parseTime(new Date(end), "HH:mm")}`
   }
+  if (period === "lesson") {
+    return `${parseTime(new Date(start), "M月D日 HH:mm")}–${parseTime(new Date(end), "HH:mm")}`
+  }
   const from = parseTime(new Date(start), "M月D日")
   const to = parseTime(new Date(end - 1), "M月D日")
   return from === to ? from : `${from}–${to}`

apps/web/src/oj/statistics/results.ts

@@ -0,0 +1,25 @@
+import { useThemeVars } from "naive-ui"
+import { JUDGE_STATUS } from "utils/constants"
+import type { SUBMISSION_RESULT } from "utils/types"
+import { useTone, type Tone } from "oj/submission/composables/tone"
+
+export function resultName(result: number) {
+  return JUDGE_STATUS[result as SUBMISSION_RESULT]?.name ?? "其他"
+}
+
+/**
+ * 结果条的颜色：答案正确绿、运行时错误橙、答案错误红、编译失败和判题中灰。
+ * 数字行那根结果条和「错得最多的题」的小条共用（原来在今日统计里）
+ */
+export function useResultColor() {
+  const theme = useThemeVars()
+  const tone = useTone()
+  return function resultColor(result: number) {
+    if (result === -2) return theme.value.textColor3
+    // 等待评分 / 判题中：还没有结果，不该和运行时错误一样是橙色
+    if (result === 6 || result === 7) return theme.value.borderColor
+    const kind: Tone = JUDGE_STATUS[result as SUBMISSION_RESULT]?.type ?? "default"
+    if (kind !== "success" && kind !== "error" && kind !== "warning") return theme.value.borderColor
+    return tone(kind).color
+  }
+}

apps/web/src/oj/submission/components/TodayStatistics.vue

@@ -2,29 +2,22 @@
 import { Icon } from "@iconify/vue"
 import { useThemeVars } from "naive-ui"
 import { getTodaySubmissionStatistics } from "oj/api"
-import { JUDGE_STATUS, LANGUAGE_SHOW_VALUE } from "utils/constants"
 import { parseTime, zonedParts } from "utils/functions"
-import type { SUBMISSION_RESULT, TodaySubmissionStatistics } from "utils/types"
-import { useTone, type Tone } from "../composables/tone"
-import { classLabel } from "../utils"
+import type { TodaySubmissionStatistics } from "utils/types"
 
 /**
- * 今日统计（设计稿「今日统计重设计」）。一般是老师在看：今天哪几个班上了课、几点到几点、
- * 错得最多的是哪几道（老师 B）。学生版从简：自己今天怎样、大家在做哪几道。
- * 盯人、实时刷新是课堂看板的活，这里不做；有班正在上课时直接引过去。
+ * 今日统计（设计稿「今日统计重设计」学生版），**只给学生**：自己今天怎样、大家在做哪几道。
+ * 老师那一版（今天哪几个班上了课、几点到几点、错得最多的题）2026-09 并进了「统计」的
+ * 「一行一节课」（oj/statistics/components/Lessons.vue），老师的提交列表上不再有这颗标签。
  */
 const emit = defineEmits<{
   close: []
   openProblem: [problem: string]
-  /** 点班级名：在提交列表的数据统计弹框里看这个班今天 */
-  openClass: [className: string]
   /** 拉到数之后把总数报回去：按钮上的数只在进页面时拉过一次，停久了会对不上 */
   loaded: [total: number]
 }>()
 
-const router = useRouter()
 const theme = useThemeVars()
-const tone = useTone()
 
 const stats = ref<TodaySubmissionStatistics | null>(null)
 const failed = ref(false)
@@ -38,8 +31,6 @@ onMounted(async () => {
   }
 })
 
-const teacher = computed(() => stats.value?.classes != null)
-
 const WEEKDAYS = ["周日", "周一", "周二", "周三", "周四", "周五", "周六"]
 
 const headText = computed(() => {
@@ -49,101 +40,6 @@ const headText = computed(() => {
   return `${p.month}月${p.day}日 ${weekday} · 截至 ${parseTime(at, "HH:mm")}`
 })
 
-function resultName(result: number) {
-  return JUDGE_STATUS[result as SUBMISSION_RESULT]?.name ?? "其他"
-}
-
-/** 结果条的颜色：答案正确绿、运行时错误橙、答案错误红、编译失败和判题中灰 */
-function resultColor(result: number) {
-  if (result === -2) return theme.value.textColor3
-  // 等待评分 / 判题中：还没有结果，不该和运行时错误一样是橙色
-  if (result === 6 || result === 7) return theme.value.borderColor
-  const kind: Tone = JUDGE_STATUS[result as SUBMISSION_RESULT]?.type ?? "default"
-  if (kind !== "success" && kind !== "error" && kind !== "warning") return theme.value.borderColor
-  return tone(kind).color
-}
-
-function percent(value: number, total: number) {
-  return total ? `${(value / total) * 100}%` : "0"
-}
-
-// ---------- 老师：各班时间轴 ----------
-
-/** 东八区的「几点几分」换成小时的小数，给时间轴定位 */
-function hourOf(value: string) {
-  const p = zonedParts(value)!
-  return p.hour + p.minute / 60
-}
-
-/** 横轴默认 7 点到 20 点（机房上课的时段），有更早更晚的提交就往外扩 */
-const axis = computed(() => {
-  const list = stats.value?.classes ?? []
-  const start = Math.min(7, ...list.map((item) => Math.floor(hourOf(item.start))))
-  const end = Math.max(20, ...list.map((item) => Math.ceil(hourOf(item.end))))
-  return { start, end, ticks: Array.from({ length: end - start + 1 }, (_, i) => start + i) }
-})
-
-function axisLeft(hour: number) {
-  const { start, end } = axis.value
-  return `${((hour - start) / (end - start)) * 100}%`
-}
-
-function barStyle(item: { start: string; end: string; live: boolean }) {
-  const from = hourOf(item.start)
-  const to = hourOf(item.end)
-  const { start, end } = axis.value
-  return {
-    left: axisLeft(from),
-    width: `max(8px, ${((to - from) / (end - start)) * 100}%)`,
-    background: item.live ? theme.value.successColor : "#3f5f87",
-  }
-}
-
-/** 横条靠近右边时文字放到条的左边，不然「497 次 · 正确率 31%」被弹框右边裁掉 */
-function textStyle(item: { start: string; end: string }) {
-  const { start, end } = axis.value
-  if ((hourOf(item.end) - start) / (end - start) > 0.72) {
-    return { right: `calc(100% - ${axisLeft(hourOf(item.start))} + 10px)` }
-  }
-  return { left: `calc(${axisLeft(hourOf(item.end))} + 14px)` }
-}
-
-const nowHour = computed(() => {
-  const at = stats.value?.asOf
-  if (!at) return null
-  const hour = hourOf(at)
-  return hour >= axis.value.start && hour <= axis.value.end ? hour : null
-})
-
-const liveClasses = computed(() => (stats.value?.classes ?? []).filter((item) => item.live))
-
-/** 23 人来了、花名册却只有 22（有个号不是学生角色）时，不写「23 / 22」 */
-function attendance(item: { userCount: number; classSize: number }) {
-  return item.classSize >= item.userCount
-    ? `${item.userCount} / ${item.classSize} 人`
-    : `${item.userCount} 人`
-}
-
-const scatteredText = computed(() =>
-  (stats.value?.scattered ?? [])
-    .map(
-      (item) =>
-        `${item.className ? classLabel(item.className) : "没填班级的"} ${item.userCount} 人 ${item.total} 次`,
-    )
-    .join("、"),
-)
-
-const judgedResults = computed(() => stats.value?.results ?? [])
-
-const languageText = computed(() => {
-  const list = stats.value?.languages ?? []
-  if (!list.length) return ""
-  if (list.length === 1) return `语言：全部是 ${LANGUAGE_SHOW_VALUE[list[0]!.language]}`
-  return `语言：${list.map((item) => `${LANGUAGE_SHOW_VALUE[item.language]} ${item.count}`).join(" · ")}`
-})
-
-// ---------- 学生 ----------
-
 const meText = computed(() => {
   const me = stats.value?.me
   if (!me) return ""
@@ -152,7 +48,7 @@ const meText = computed(() => {
 </script>
 
 <template>
-  <div class="today" :class="{ wide: teacher }">
+  <div class="today">
     <div class="head">
       <b class="title">今日统计</b>
       <n-text depth="3" class="small">{{ headText }}</n-text>
@@ -173,186 +69,6 @@ const meText = computed(() => {
         <n-text depth="3">第一条提交进来之后这里就有数了</n-text>
       </div>
 
-      <!-- ==================== 老师 ==================== -->
-      <template v-else-if="teacher">
-        <div class="numbers">
-          <div>
-            <b>{{ stats.total }}</b
-            ><span>次提交</span>
-          </div>
-          <div>
-            <b>{{ stats.userCount }}</b
-            ><span>人</span>
-          </div>
-          <div>
-            <b>{{ stats.correctRate }}%</b><span>提交正确率</span>
-          </div>
-          <div>
-            <b>{{ stats.classes!.length }}</b
-            ><span>个班上了课</span>
-          </div>
-        </div>
-
-        <div
-          v-if="liveClasses.length"
-          class="live"
-          :style="{ background: tone('success').background, color: tone('success').color }"
-        >
-          <span>
-            {{ liveClasses.map((item) => classLabel(item.className)).join("、") }}正在上课
-          </span>
-          <span class="spacer"></span>
-          <a href="#" class="live-link" @click.prevent="router.push('/classroom')">
-            <Icon icon="ph:monitor" :width="14" />去课堂看板
-          </a>
-        </div>
-
-        <template v-if="stats.classes!.length">
-          <div class="section-title">
-            <b>今天哪几个班上了课</b>
-            <n-text depth="3" class="small">点班级名去数据统计看今天</n-text>
-          </div>
-          <div class="timeline">
-            <div v-for="item in stats.classes" :key="item.className" class="lane">
-              <div class="lane-label">
-                <a href="#" class="lane-name" @click.prevent="emit('openClass', item.className)">
-                  {{ classLabel(item.className) }}
-                </a>
-                <n-text depth="3" class="tiny">
-                  {{ attendance(item) }} · {{ item.fromProblemSet ? "题单" : ""
-                  }}{{ item.problemCount }} 道题
-                </n-text>
-              </div>
-              <div class="lane-track">
-                <span
-                  v-for="tick in axis.ticks"
-                  :key="tick"
-                  class="grid"
-                  :style="{ left: axisLeft(tick) }"
-                ></span>
-                <span class="lane-bar" :style="barStyle(item)"></span>
-                <span class="lane-text" :style="textStyle(item)">
-                  {{ item.total }} 次 ·
-                  {{ item.live ? "上课中" : `正确率 ${Math.round(item.correctRate)}%` }}
-                </span>
-                <span
-                  v-if="nowHour !== null"
-                  class="now"
-                  :style="{ left: axisLeft(nowHour) }"
-                ></span>
-              </div>
-            </div>
-            <div class="lane axis-row">
-              <div class="lane-label"></div>
-              <div class="lane-track axis">
-                <span v-for="tick in axis.ticks" :key="tick" :style="{ left: axisLeft(tick) }">
-                  {{ tick }}
-                </span>
-                <span
-                  v-if="nowHour !== null"
-                  class="now-label"
-                  :style="{ left: axisLeft(nowHour) }"
-                >
-                  现在
-                </span>
-              </div>
-            </div>
-          </div>
-        </template>
-        <n-text v-if="scatteredText" depth="3" class="small">
-          {{ stats.classes!.length ? "另有零散提交：" : "今天没有哪个班一起上课，零散提交："
-          }}{{ scatteredText }}
-        </n-text>
-
-        <template v-if="stats.hardProblems?.length">
-          <div class="section-title">
-            <b>错得最多的题</b>
-            <n-text depth="3" class="small">按没过的次数</n-text>
-          </div>
-          <table class="hard">
-            <thead>
-              <tr>
-                <th>题目</th>
-                <th>哪个班</th>
-                <th>提交</th>
-                <th>没过的原因</th>
-                <th class="right">做对</th>
-              </tr>
-            </thead>
-            <tbody>
-              <tr v-for="item in stats.hardProblems" :key="item.problemDisplayId">
-                <td class="hard-title">
-                  <a href="#" @click.prevent="emit('openProblem', item.problemDisplayId)">
-                    <n-text depth="3">{{ item.problemDisplayId }}</n-text> {{ item.problemTitle }}
-                  </a>
-                </td>
-                <td>
-                  <n-text depth="2">{{ item.className ? classLabel(item.className) : "—" }}</n-text>
-                </td>
-                <td>{{ item.total }} 次</td>
-                <td>
-                  <span class="mini">
-                    <span
-                      :style="{
-                        width: percent(item.accepted, item.total),
-                        background: resultColor(0),
-                      }"
-                    ></span>
-                    <span
-                      v-for="fail in item.failures"
-                      :key="fail.result"
-                      :style="{
-                        width: percent(fail.count, item.total),
-                        background: resultColor(fail.result),
-                      }"
-                    ></span>
-                  </span>
-                  <n-text depth="2" class="small">
-                    {{ resultName(item.failures[0]!.result) }} {{ item.failures[0]!.count }}
-                  </n-text>
-                </td>
-                <td
-                  class="right"
-                  :style="{
-                    color: item.acceptedUsers < item.userCount ? tone('error').color : undefined,
-                    fontWeight: item.acceptedUsers < item.userCount ? 600 : undefined,
-                  }"
-                >
-                  {{ item.acceptedUsers }} / {{ item.userCount }} 人
-                </td>
-              </tr>
-            </tbody>
-          </table>
-        </template>
-
-        <div class="foot">
-          <div class="foot-bar">
-            <div class="results">
-              <span
-                v-for="item in judgedResults"
-                :key="item.result"
-                :style="{
-                  width: percent(item.count, stats.total),
-                  background: resultColor(item.result),
-                }"
-              ></span>
-            </div>
-            <div class="legend">
-              <span v-for="item in judgedResults.slice(0, 5)" :key="item.result">
-                <i :style="{ background: resultColor(item.result) }"></i
-                >{{ resultName(item.result) }}
-                <b>{{ item.count }}</b>
-              </span>
-            </div>
-          </div>
-          <n-text depth="3" class="small foot-meta">
-            {{ languageText }} ·
-            {{ stats.flowchartCount ? `流程图 ${stats.flowchartCount} 张` : "流程图今天没人画" }}
-          </n-text>
-        </div>
-      </template>
-
-      <!-- ==================== 学生：从简 ==================== -->
       <template v-else>
         <div v-if="meText" class="me">
           <b>你今天</b>
@@ -412,10 +128,6 @@ const meText = computed(() => {
   overflow: hidden;
 }
 
-.today.wide {
-  width: min(880px, calc(100vw - 32px));
-}
-
 .head {
   flex: none;
   display: flex;
@@ -470,10 +182,6 @@ const meText = computed(() => {
   font-size: 13px;
 }
 
-.tiny {
-  font-size: 12px;
-}
-
 .center {
   display: flex;
   justify-content: center;
@@ -521,200 +229,12 @@ const meText = computed(() => {
   color: v-bind("theme.textColor3");
 }
 
-.live {
-  display: flex;
-  align-items: center;
-  padding: 10px 14px;
-  border-radius: 8px;
-}
-
-.live-link {
-  color: inherit;
-  font-weight: 600;
-  text-decoration: none;
-  display: inline-flex;
-  align-items: center;
-  gap: 4px;
-}
-
 .section-title {
   display: flex;
   align-items: baseline;
   gap: 10px;
 }
 
-.timeline {
-  display: flex;
-  flex-direction: column;
-}
-
-.lane {
-  display: flex;
-  min-height: 42px;
-  border-bottom: 1px solid v-bind("theme.dividerColor");
-}
-
-.lane.axis-row {
-  min-height: 24px;
-  border-bottom: 0;
-}
-
-.lane-label {
-  width: 150px;
-  flex: none;
-  display: flex;
-  flex-direction: column;
-  justify-content: center;
-}
-
-.lane-name {
-  font-weight: 600;
-  color: v-bind("theme.textColor1");
-  text-decoration: none;
-}
-
-.lane-name:hover {
-  color: v-bind("theme.primaryColor");
-}
-
-.lane-track {
-  position: relative;
-  flex: 1;
-}
-
-.grid {
-  position: absolute;
-  top: 0;
-  bottom: 0;
-  width: 1px;
-  background: v-bind("theme.dividerColor");
-}
-
-.lane-bar {
-  position: absolute;
-  top: 50%;
-  height: 16px;
-  margin-top: -8px;
-  border-radius: 4px;
-}
-
-.lane-text {
-  position: absolute;
-  top: 50%;
-  transform: translateY(-50%);
-  font-size: 13px;
-  white-space: nowrap;
-  color: v-bind("theme.textColor2");
-}
-
-.now {
-  position: absolute;
-  top: -4px;
-  bottom: -4px;
-  width: 2px;
-  background: v-bind("theme.successColor");
-}
-
-.axis span {
-  position: absolute;
-  top: 4px;
-  transform: translateX(-50%);
-  font-size: 11px;
-  color: v-bind("theme.textColor3");
-}
-
-.axis .now-label {
-  top: 4px;
-  font-weight: 600;
-  color: v-bind("theme.successColor");
-  background: v-bind("theme.cardColor");
-  padding: 0 2px;
-}
-
-.hard {
-  width: 100%;
-  border-collapse: collapse;
-  font-size: 13px;
-}
-
-.hard th {
-  text-align: left;
-  font-weight: normal;
-  color: v-bind("theme.textColor3");
-  padding: 4px 8px 6px 0;
-  border-bottom: 1px solid v-bind("theme.dividerColor");
-}
-
-.hard td {
-  padding: 8px 8px 8px 0;
-  border-bottom: 1px solid v-bind("theme.dividerColor");
-  white-space: nowrap;
-}
-
-.hard .right {
-  text-align: right;
-  padding-right: 0;
-}
-
-.hard-title a {
-  color: v-bind("theme.textColor1");
-  text-decoration: none;
-}
-
-.hard-title a:hover {
-  color: v-bind("theme.primaryColor");
-}
-
-.mini {
-  display: inline-flex;
-  width: 70px;
-  height: 8px;
-  border-radius: 2px;
-  overflow: hidden;
-  gap: 1px;
-  margin-right: 8px;
-  vertical-align: middle;
-}
-
-.foot {
-  display: flex;
-  align-items: flex-end;
-  gap: 24px;
-  flex-wrap: wrap;
-}
-
-.foot-bar {
-  flex: 1;
-  min-width: 280px;
-  display: flex;
-  flex-direction: column;
-  gap: 8px;
-}
-
-.results {
-  display: flex;
-  height: 10px;
-  border-radius: 3px;
-  overflow: hidden;
-  gap: 1px;
-}
-
-.legend {
-  display: flex;
-  flex-wrap: wrap;
-  gap: 4px 14px;
-  font-size: 13px;
-  color: v-bind("theme.textColor2");
-}
-
-.legend i {
-  display: inline-block;
-  width: 9px;
-  height: 9px;
-  border-radius: 2px;
-  margin-right: 5px;
-}
-
 .me {
   display: flex;
   gap: 12px;

apps/web/src/oj/submission/list.vue

@@ -11,7 +11,7 @@ import {
   getTodaySubmissionCount,
   retryFlowchartSubmission,
 } from "oj/api"
-import { DEFAULT_PERIOD, type Period } from "oj/statistics/period"
+import { DEFAULT_PERIOD } from "oj/statistics/period"
 import { useContestStore } from "oj/store/contest"
 import Pagination from "shared/components/Pagination.vue"
 import { useBreakpoints } from "shared/composables/breakpoints"
@@ -38,7 +38,7 @@ import { classLabel, submissionClockText, submissionDayText } from "./utils"
  *
  * 老师课上的三种用法 —— 一条条翻全班的代码、看某一个学生、看完成情况 —— 前两种在
  * 这一页里做完：↑ ↓ 换条，右边跟着换，不再「点开弹框 → 关掉 → 点下一行」。
- * 完成情况在课堂看板和「数据统计」里，这页不重复造一张表。
+ * 完成情况在课堂看板和「统计」里，这页不重复造一张表。
  */
 
 // 右栏和今日统计弹框都不在关键路径上：右栏要等选中一条才有内容，弹框默认关着
@@ -190,7 +190,8 @@ async function getTodayCount() {
 
 onMounted(() => {
   listSubmissions()
-  if (route.name === "submissions") getTodayCount()
+  // 「今日统计 N」只给学生：老师那一版并进了「统计」
+  if (route.name === "submissions" && !teacher.value) getTodayCount()
 })
 
 watchDebounced(() => [query.username, query.problem], listSubmissions, {
@@ -483,9 +484,6 @@ const scope = computed({
   },
 })
 
-/** 1366 以下（机房 1280 的屏）老师那排放不下：「今日统计」只留图标和数字 */
-const narrowBar = useMediaQuery("(max-width: 1365px)")
-
 const today = computed({
   get: () => query.today === "1",
   set: (value: boolean) => (query.today = value ? "1" : "0"),
@@ -564,7 +562,7 @@ function filterUser(username: string) {
 }
 
 /**
- * 「数据统计」弹框的查询条件。每次打开从这张列表现在的班级 / 学生 / 题号 / 代码或流程图
+ * 「统计」弹框的查询条件。每次打开从这张列表现在的班级 / 学生 / 题号 / 代码或流程图
  * 带进去（「今天」带过去就是统计的「今天」）；时间段沿用上次在弹框里选的
  */
 const statsQuery = reactive({
@@ -577,14 +575,18 @@ const statsQuery = reactive({
   to: "",
 })
 
-function openStatistics(preset?: { className: string; period: Period }) {
-  todayPanel.value = false
+/**
+ * 老师的「统计」：带着这张列表现在的班级 / 学生 / 题号 / 代码或流程图打开。原来旁边还有一颗
+ * 「今日统计」，和「数据统计」名字分不清（用户说的），老师那一版并进来了 —— 什么都没筛时
+ * 打开就是「一行一节课」，选「今天」就是原来今日统计看的东西
+ */
+function openStatistics() {
   Object.assign(statsQuery, {
     tab: flowMode.value ? "flow" : "code",
-    className: preset ? preset.className : query.className,
-    username: preset ? "" : query.username,
-    problem: preset ? "" : query.problem,
-    ...(preset ? { period: preset.period } : query.today === "1" ? { period: "today" } : {}),
+    className: query.className,
+    username: query.username,
+    problem: query.problem,
+    ...(query.today === "1" ? { period: "today" } : {}),
   })
   statsPanel.value = true
 }
@@ -814,27 +816,28 @@ function dayBreak(index: number) {
       <n-button size="small" quaternary @click="clear">清空</n-button>
 
       <div class="spacer"></div>
+      <!-- 老师只有「统计」（今日统计并进去了）；学生看不到统计，仍是「今日统计」 -->
       <n-button
-        v-if="route.name === 'submissions' && !flowMode"
+        v-if="teacher && route.name === 'submissions'"
+        size="small"
+        quaternary
+        title="统计：这节课、今天，或者回头看以前的课"
+        @click="openStatistics()"
+      >
+        <template #icon><Icon icon="ph:chart-bar" /></template>
+        统计
+      </n-button>
+      <n-button
+        v-else-if="route.name === 'submissions' && !flowMode"
         size="small"
         quaternary
         :title="`今日统计：今天全站 ${todayCount} 条`"
         @click="toggleTodayPanel(true)"
       >
         <template #icon><Icon icon="ph:chart-bar" /></template>
-        <template v-if="!(teacher && narrowBar)">今日统计</template>
+        今日统计
         <span v-if="todayCount" class="count">{{ todayCount }}</span>
       </n-button>
-      <n-button
-        v-if="teacher && route.name === 'submissions'"
-        size="small"
-        quaternary
-        title="数据统计：按班级、题号、时间段回头看"
-        @click="openStatistics()"
-      >
-        <template #icon><Icon icon="ph:chart-pie-slice" /></template>
-        数据统计
-      </n-button>
     </div>
 
     <!-- 手机：只留全部/我的，其余收进「筛选」 -->
@@ -1109,7 +1112,6 @@ function dayBreak(index: number) {
       @close="todayPanel = false"
       @loaded="(total: number) => (todayCount = total)"
       @open-problem="(id: string) => openProblem({ problemDisplayId: id } as Row)"
-      @open-class="(name: string) => openStatistics({ className: name, period: 'today' })"
     />
   </n-modal>
 

apps/web/src/shared/components/Header.vue

@@ -255,7 +255,7 @@ const options = computed<Array<DropdownOption | DropdownDividerOption>>(() => {
     <div class="actions">
       <ProblemJumpBox v-if="isDesktop" :compact="compact" />
       <template v-if="isDesktop && collabStore.isTeacher">
-        <!-- 和提交列表的「今日统计」「数据统计」同一种按钮：平时没底色，悬停出底色 -->
+        <!-- 和提交列表的「统计」同一种按钮：平时没底色，悬停出底色 -->
         <n-button
           quaternary
           class="tool-link"