diff --git a/apps/api/src/http.ts b/apps/api/src/http.ts
index 73bd31e..d2993b7 100644
--- a/apps/api/src/http.ts
+++ b/apps/api/src/http.ts
@@ -6,7 +6,7 @@ export function success<T>(c: Context, data: T, status = 200) {
 
 export function failure(
   c: Context,
-  status: 400 | 401 | 403 | 404 | 409 | 429 | 500 | 502,
+  status: 400 | 401 | 403 | 404 | 409 | 429 | 500 | 501 | 502,
   code: string,
   message: string,
 ) {
diff --git a/apps/api/src/routes/admin/index.ts b/apps/api/src/routes/admin/index.ts
index 895c867..2b32bc3 100644
--- a/apps/api/src/routes/admin/index.ts
+++ b/apps/api/src/routes/admin/index.ts
@@ -6,6 +6,7 @@ import { adminAchievementRoutes } from "./achievement"
 import { adminAiRoutes } from "./ai"
 import { adminConfRoutes } from "./conf"
 import { adminContestRoutes } from "./contest"
+import { adminProblemRoutes } from "./problem"
 import { adminProblemSetRoutes } from "./problemset"
 import { adminTagRoutes } from "./tag"
 import { adminAnnouncementRoutes } from "./announcement"
@@ -26,6 +27,7 @@ adminRoutes.route("/", adminAchievementRoutes)
 adminRoutes.route("/", adminAiRoutes)
 adminRoutes.route("/", adminConfRoutes)
 adminRoutes.route("/", adminContestRoutes)
+adminRoutes.route("/", adminProblemRoutes)
 adminRoutes.route("/", adminProblemSetRoutes)
 adminRoutes.route("/", adminTagRoutes)
 adminRoutes.route("/", adminAnnouncementRoutes)
diff --git a/apps/api/src/routes/admin/problem.ts b/apps/api/src/routes/admin/problem.ts
new file mode 100644
index 0000000..9878d42
--- /dev/null
+++ b/apps/api/src/routes/admin/problem.ts
@@ -0,0 +1,528 @@
+import {
+  addContestProblemRequestSchema,
+  adminProblemListItemSchema,
+  adminProblemListSchema,
+  adminProblemSchema,
+  createProblemRequestSchema,
+  makeProblemPublicRequestSchema,
+  updateProblemRequestSchema,
+} from "@oj2/contract"
+import { and, count, desc, eq, ilike, inArray, isNull, ne, or, sql } from "drizzle-orm"
+import { Hono } from "hono"
+
+import { requireProblemPermission, type AppEnv } from "../../auth/middleware"
+import type { AuthUser } from "../../auth/session"
+import { db, schema } from "../../db"
+import { failure, success } from "../../http"
+import { contestStatus } from "../../services/contest"
+import { objectValue, queryInteger, sampleUser, stringArray } from "../helpers"
+
+export const adminProblemRoutes = new Hono<AppEnv>()
+
+type ProblemRow = typeof schema.problem.$inferSelect
+
+function canManageAll(user: AuthUser) {
+  return user.adminType === "Super Admin" || user.problemPermission === "All"
+}
+
+/**
+ * 题目归属判断。比赛题看**比赛**的创建者，公开题看题目自己的创建者 ——
+ * 对齐旧后端：`ensure_created_by(problem.contest, user)` vs `ensure_created_by(problem, user)`。
+ * 一道比赛题的 created_by 可能是克隆时的操作人，跟谁有权改它没关系。
+ */
+async function canEdit(user: AuthUser, problem: ProblemRow) {
+  if (user.adminType === "Super Admin") return true
+  if (problem.contestId === null) {
+    return canManageAll(user) || problem.createdById === user.id
+  }
+  const [contest] = await db.select({ createdById: schema.contest.createdById })
+    .from(schema.contest).where(eq(schema.contest.id, problem.contestId)).limit(1)
+  return Boolean(contest && contest.createdById === user.id)
+}
+
+async function tagNames(problemId: number) {
+  const rows = await db.select({ name: schema.problemTag.name }).from(schema.problemTags)
+    .innerJoin(schema.problemTag, eq(schema.problemTags.problemtagId, schema.problemTag.id))
+    .where(eq(schema.problemTags.problemId, problemId))
+  return rows.map((row) => row.name)
+}
+
+/** 把标签名解析成 id：去空格、大小写不敏感复用已有标签，没有才新建。对齐旧 resolve_tags */
+async function resolveTags(tx: typeof db, names: string[]) {
+  const ids: number[] = []
+  const seen = new Set<string>()
+  for (const raw of names) {
+    const name = raw.trim()
+    if (!name || seen.has(name.toLowerCase())) continue
+    seen.add(name.toLowerCase())
+    const [existing] = await tx.select({ id: schema.problemTag.id }).from(schema.problemTag)
+      .where(sql`lower(${schema.problemTag.name}) = lower(${name})`).limit(1)
+    if (existing) { ids.push(existing.id); continue }
+    const [created] = await tx.insert(schema.problemTag).values({ name })
+      .returning({ id: schema.problemTag.id })
+    ids.push(created!.id)
+  }
+  return ids
+}
+
+async function setTags(tx: typeof db, problemId: number, names: string[]) {
+  const ids = await resolveTags(tx, names)
+  await tx.delete(schema.problemTags).where(eq(schema.problemTags.problemId, problemId))
+  if (ids.length) {
+    await tx.insert(schema.problemTags).values(ids.map((problemtagId) => ({ problemId, problemtagId })))
+  }
+}
+
+async function serialize(row: ProblemRow) {
+  const [[creator], tags] = await Promise.all([
+    db.select({ id: schema.user.id, username: schema.user.username, realName: schema.userProfile.realName })
+      .from(schema.user).leftJoin(schema.userProfile, eq(schema.userProfile.userId, schema.user.id))
+      .where(eq(schema.user.id, row.createdById)).limit(1),
+    tagNames(row.id),
+  ])
+  return adminProblemSchema.parse({
+    id: row.id,
+    _id: row.displayId,
+    title: row.title,
+    description: row.description,
+    inputDescription: row.inputDescription,
+    outputDescription: row.outputDescription,
+    samples: Array.isArray(row.samples) ? row.samples : [],
+    testCaseId: row.testCaseId,
+    testCaseScore: Array.isArray(row.testCaseScore) ? row.testCaseScore : [],
+    hint: row.hint,
+    languages: stringArray(row.languages),
+    template: objectValue(row.template),
+    createTime: row.createTime,
+    lastUpdateTime: row.lastUpdateTime,
+    timeLimit: row.timeLimit,
+    memoryLimit: row.memoryLimit,
+    visible: row.visible,
+    difficulty: row.difficulty,
+    source: row.source,
+    submissionNumber: row.submissionNumber,
+    acceptedNumber: row.acceptedNumber,
+    statisticInfo: objectValue(row.statisticInfo),
+    shareSubmission: row.shareSubmission,
+    contestId: row.contestId,
+    createdBy: sampleUser(creator ?? { id: row.createdById, username: "" }, creator?.realName),
+    isPublic: row.isPublic,
+    tags,
+    allowFlowchart: row.allowFlowchart,
+    showFlowchart: row.showFlowchart,
+    mermaidCode: row.mermaidCode,
+    flowchartHint: row.flowchartHint,
+    astRules: row.astRules,
+    answers: Array.isArray(row.answers) ? row.answers : [],
+    prompt: row.prompt,
+    sqlConfig: row.sqlConfig ? objectValue(row.sqlConfig) : null,
+    sqlDisplay: row.sqlDisplay ? objectValue(row.sqlDisplay) : null,
+  })
+}
+
+/**
+ * 非 SQL 题的公共校验，对齐旧 `ProblemBase.common_checks` 的 else 分支。
+ *
+ * SQL 分支在这里**只做前置校验、不生成 sqlDisplay** —— 生成需要跑 SQLite，
+ * 而新后端还没有 SQL 判题链路（旧 judge/sql_runner.py 378 行无对应实现）。
+ * 因此新建 SQL 题会被拒绝，编辑 SQL 题则保留原有 sqlDisplay 不动，不会把已有数据弄坏。
+ */
+function commonChecks(data: {
+  languages: string[]
+  inputDescription: string
+  outputDescription: string
+  samples: unknown[]
+  sqlConfig: Record<string, unknown> | null
+  answers: Record<string, unknown>[]
+}): { error: string } | { sql: boolean } {
+  if (data.languages.includes("SQL")) {
+    if (data.languages.length !== 1) return { error: "SQL problem cannot be mixed with other languages" }
+    if (!data.sqlConfig) return { error: "SQL problem requires sql_config" }
+    const hasAnswer = data.answers.some((item) =>
+      item.language === "SQL" && typeof item.code === "string" && item.code.trim())
+    if (!hasAnswer) return { error: "SQL problem requires a SQL reference answer" }
+    return { sql: true }
+  }
+  if (!data.inputDescription || !data.outputDescription) {
+    return { error: "Input and output description are required" }
+  }
+  if (data.samples.length === 0) return { error: "Samples are required" }
+  return { sql: false }
+}
+
+const SQL_NOT_SUPPORTED =
+  "新后端尚未实现 SQL 判题链路（题目页展示数据需要跑 SQLite 生成），暂不能新建 SQL 题。已有 SQL 题可以正常编辑，其展示数据保持不变。"
+
+function problemValues(data: ReturnType<typeof createProblemRequestSchema.parse>, isSql: boolean) {
+  return {
+    displayId: data._id,
+    title: data.title,
+    description: data.description,
+    inputDescription: data.inputDescription,
+    outputDescription: data.outputDescription,
+    samples: data.samples,
+    testCaseId: data.testCaseId,
+    testCaseScore: data.testCaseScore,
+    hint: data.hint,
+    languages: data.languages,
+    template: data.template,
+    timeLimit: data.timeLimit,
+    memoryLimit: data.memoryLimit,
+    visible: data.visible,
+    difficulty: data.difficulty,
+    source: data.source,
+    shareSubmission: data.shareSubmission,
+    allowFlowchart: data.allowFlowchart,
+    showFlowchart: data.showFlowchart,
+    mermaidCode: data.mermaidCode,
+    flowchartHint: data.flowchartHint,
+    astRules: data.astRules ?? null,
+    answers: data.answers,
+    prompt: data.prompt,
+    // 防脏数据：非 SQL 题不应携带 SQL 配置，对齐旧 common_checks
+    sqlConfig: isSql ? data.sqlConfig : null,
+  }
+}
+
+// ---------------------------------------------------------------- 公开题目
+
+adminProblemRoutes.get("/problems", requireProblemPermission, async (c) => {
+  const limit = queryInteger(c.req.query("limit"), 10, { min: 1, max: 250 })
+  const offset = queryInteger(c.req.query("offset"), 0, { min: 0 })
+  const user = c.get("user")!
+  const filters = [isNull(schema.problem.contestId)]
+  if (!canManageAll(user)) filters.push(eq(schema.problem.createdById, user.id))
+  const author = c.req.query("author")?.trim()
+  const keyword = c.req.query("keyword")?.trim()
+  const tagId = c.req.query("tagId")?.trim()
+  if (author) filters.push(eq(schema.user.username, author))
+  if (keyword) {
+    filters.push(or(
+      ilike(schema.problem.title, `%${keyword}%`),
+      ilike(schema.problem.displayId, `%${keyword}%`),
+    )!)
+  }
+  if (tagId) {
+    filters.push(inArray(schema.problem.id,
+      db.select({ id: schema.problemTags.problemId }).from(schema.problemTags)
+        .where(eq(schema.problemTags.problemtagId, Number(tagId)))))
+  }
+  const where = and(...filters)
+  const [totalRow, rows] = await Promise.all([
+    db.select({ value: count() }).from(schema.problem)
+      .innerJoin(schema.user, eq(schema.problem.createdById, schema.user.id)).where(where),
+    db.select({ problem: schema.problem, user: schema.user, realName: schema.userProfile.realName })
+      .from(schema.problem)
+      .innerJoin(schema.user, eq(schema.problem.createdById, schema.user.id))
+      .leftJoin(schema.userProfile, eq(schema.userProfile.userId, schema.user.id))
+      .where(where).orderBy(desc(schema.problem.createTime)).limit(limit).offset(offset),
+  ])
+  return success(c, adminProblemListSchema.parse({
+    results: await Promise.all(rows.map(async ({ problem, user: creator, realName }) =>
+      adminProblemListItemSchema.parse({
+        id: problem.id,
+        _id: problem.displayId,
+        title: problem.title,
+        createdBy: sampleUser(creator, realName),
+        visible: problem.visible,
+        createTime: problem.createTime,
+        difficulty: problem.difficulty,
+        tags: await tagNames(problem.id),
+        hasAstRules: problem.astRules !== null,
+        allowFlowchart: problem.allowFlowchart,
+        showFlowchart: problem.showFlowchart,
+        topReaction: null,
+      }))),
+    total: totalRow[0]?.value ?? 0,
+  }))
+})
+
+adminProblemRoutes.get("/problems/:id", requireProblemPermission, async (c) => {
+  const [row] = await db.select().from(schema.problem)
+    .where(eq(schema.problem.id, queryInteger(c.req.param("id"), 0, { min: 1 }))).limit(1)
+  if (!row) return failure(c, 404, "problem-not-found", "Problem does not exist")
+  if (!(await canEdit(c.get("user")!, row))) {
+    return failure(c, 404, "problem-not-found", "Problem does not exist")
+  }
+  return success(c, await serialize(row))
+})
+
+adminProblemRoutes.post("/problems", requireProblemPermission, async (c) => {
+  const parsed = createProblemRequestSchema.safeParse(await c.req.json().catch(() => null))
+  if (!parsed.success) {
+    return failure(c, 400, "invalid-request", parsed.error.issues[0]?.message ?? "参数错误")
+  }
+  const checked = commonChecks(parsed.data)
+  if ("error" in checked) return failure(c, 400, "invalid-problem", checked.error)
+  if (checked.sql) return failure(c, 501, "sql-not-supported", SQL_NOT_SUPPORTED)
+
+  const [duplicate] = await db.select({ id: schema.problem.id }).from(schema.problem)
+    .where(and(eq(schema.problem.displayId, parsed.data._id), isNull(schema.problem.contestId))).limit(1)
+  if (duplicate) return failure(c, 409, "display-id-exists", "Display ID already exists")
+
+  const now = new Date().toISOString()
+  const created = await db.transaction(async (tx) => {
+    const [row] = await tx.insert(schema.problem).values({
+      ...problemValues(parsed.data, false),
+      contestId: null,
+      createdById: c.get("user")!.id,
+      createTime: now,
+      lastUpdateTime: now,
+      submissionNumber: 0,
+      acceptedNumber: 0,
+      statisticInfo: {},
+      isPublic: false,
+      sqlDisplay: null,
+    }).returning()
+    await setTags(tx as unknown as typeof db, row!.id, parsed.data.tags)
+    return row!
+  })
+  return success(c, await serialize(created), 201)
+})
+
+adminProblemRoutes.put("/problems/:id", requireProblemPermission, async (c) => {
+  const id = queryInteger(c.req.param("id"), 0, { min: 1 })
+  const parsed = updateProblemRequestSchema.safeParse(await c.req.json().catch(() => null))
+  if (!parsed.success) {
+    return failure(c, 400, "invalid-request", parsed.error.issues[0]?.message ?? "参数错误")
+  }
+  const [existing] = await db.select().from(schema.problem).where(eq(schema.problem.id, id)).limit(1)
+  if (!existing) return failure(c, 404, "problem-not-found", "Problem does not exist")
+  if (!(await canEdit(c.get("user")!, existing))) {
+    return failure(c, 404, "problem-not-found", "Problem does not exist")
+  }
+  const checked = commonChecks(parsed.data)
+  if ("error" in checked) return failure(c, 400, "invalid-problem", checked.error)
+
+  // 题号唯一性的作用域跟着题目走：公开题在全部公开题里唯一，比赛题在本场比赛内唯一
+  const [duplicate] = await db.select({ id: schema.problem.id }).from(schema.problem)
+    .where(and(
+      eq(schema.problem.displayId, parsed.data._id),
+      existing.contestId === null
+        ? isNull(schema.problem.contestId)
+        : eq(schema.problem.contestId, existing.contestId),
+      ne(schema.problem.id, id),
+    )).limit(1)
+  if (duplicate) return failure(c, 409, "display-id-exists", "Display ID already exists")
+
+  const updated = await db.transaction(async (tx) => {
+    const [row] = await tx.update(schema.problem).set({
+      ...problemValues(parsed.data, checked.sql),
+      lastUpdateTime: new Date().toISOString(),
+      // SQL 题的 sqlDisplay 原样保留：重新生成需要跑 SQLite，新后端还没有那条链路。
+      // 不动它比生成一个错的更安全 —— 它直接决定题目页给学生看的表结构与期望结果。
+    }).where(eq(schema.problem.id, id)).returning()
+    await setTags(tx as unknown as typeof db, id, parsed.data.tags)
+    return row!
+  })
+  return success(c, await serialize(updated))
+})
+
+// 公开题与比赛题共用一条删除路由。旧接口分成两个（admin/problem 与
+// admin/contest/problem），但两边都只按题目 id 取、比赛是从题目推导出来的，
+// 分开没有意义，还逼前端多传一个它未必知道的 contestId。
+adminProblemRoutes.delete("/problems/:id", requireProblemPermission, async (c) => {
+  const id = queryInteger(c.req.param("id"), 0, { min: 1 })
+  const [existing] = await db.select().from(schema.problem).where(eq(schema.problem.id, id)).limit(1)
+  if (!existing) return failure(c, 404, "problem-not-found", "Problem does not exists")
+  if (!(await canEdit(c.get("user")!, existing))) {
+    return failure(c, 404, "problem-not-found", "Problem does not exists")
+  }
+  return deleteProblem(c, id)
+})
+
+/**
+ * 删题的共用实现。子表全是 NO ACTION 外键，Django 的级联在应用层，得手工清。
+ * 测试用例目录**不删** —— 与旧后端一致（它把 rmtree 注释掉了）。
+ * 删错了还能从磁盘捞回来，而误删的测试数据没有别处备份；孤儿目录另有清理入口。
+ */
+async function deleteProblem(c: Parameters<typeof success>[0], id: number) {
+  const [submissions] = await db.select({ value: count() }).from(schema.submission)
+    .where(eq(schema.submission.problemId, id))
+  if ((submissions?.value ?? 0) > 0) {
+    return failure(c, 409, "problem-has-submissions", "该题目已有提交记录，不能删除")
+  }
+  await db.transaction(async (tx) => {
+    await tx.delete(schema.problemTags).where(eq(schema.problemTags.problemId, id))
+    await tx.delete(schema.problemsetProblem).where(eq(schema.problemsetProblem.problemId, id))
+    await tx.delete(schema.flowchartSubmission).where(eq(schema.flowchartSubmission.problemId, id))
+    await tx.delete(schema.reaction).where(eq(schema.reaction.problemId, id))
+    await tx.delete(schema.problem).where(eq(schema.problem.id, id))
+  })
+  return success(c, null)
+}
+
+// ---------------------------------------------------------------- 比赛题目
+
+adminProblemRoutes.get("/contests/:contestId/problems", requireProblemPermission, async (c) => {
+  const contestId = queryInteger(c.req.param("contestId"), 0, { min: 1 })
+  const [contest] = await db.select().from(schema.contest).where(eq(schema.contest.id, contestId)).limit(1)
+  const user = c.get("user")!
+  if (!contest || (user.adminType !== "Super Admin" && contest.createdById !== user.id)) {
+    return failure(c, 404, "contest-not-found", "Contest does not exist")
+  }
+  const limit = queryInteger(c.req.query("limit"), 10, { min: 1, max: 250 })
+  const offset = queryInteger(c.req.query("offset"), 0, { min: 0 })
+  const filters = [eq(schema.problem.contestId, contestId)]
+  const keyword = c.req.query("keyword")?.trim()
+  if (keyword) filters.push(ilike(schema.problem.title, `%${keyword}%`))
+  const where = and(...filters)
+  const [totalRow, rows] = await Promise.all([
+    db.select({ value: count() }).from(schema.problem).where(where),
+    db.select({ problem: schema.problem, user: schema.user, realName: schema.userProfile.realName })
+      .from(schema.problem)
+      .innerJoin(schema.user, eq(schema.problem.createdById, schema.user.id))
+      .leftJoin(schema.userProfile, eq(schema.userProfile.userId, schema.user.id))
+      .where(where).orderBy(desc(schema.problem.createTime)).limit(limit).offset(offset),
+  ])
+  return success(c, adminProblemListSchema.parse({
+    results: await Promise.all(rows.map(async ({ problem, user: creator, realName }) =>
+      adminProblemListItemSchema.parse({
+        id: problem.id,
+        _id: problem.displayId,
+        title: problem.title,
+        createdBy: sampleUser(creator, realName),
+        visible: problem.visible,
+        createTime: problem.createTime,
+        difficulty: problem.difficulty,
+        tags: await tagNames(problem.id),
+        hasAstRules: problem.astRules !== null,
+        allowFlowchart: problem.allowFlowchart,
+        showFlowchart: problem.showFlowchart,
+        topReaction: null,
+      }))),
+    total: totalRow[0]?.value ?? 0,
+  }))
+})
+
+adminProblemRoutes.post("/contests/:contestId/problems", requireProblemPermission, async (c) => {
+  const contestId = queryInteger(c.req.param("contestId"), 0, { min: 1 })
+  const [contest] = await db.select().from(schema.contest).where(eq(schema.contest.id, contestId)).limit(1)
+  const user = c.get("user")!
+  if (!contest || (user.adminType !== "Super Admin" && contest.createdById !== user.id)) {
+    return failure(c, 404, "contest-not-found", "Contest does not exist")
+  }
+  const parsed = createProblemRequestSchema.safeParse(await c.req.json().catch(() => null))
+  if (!parsed.success) {
+    return failure(c, 400, "invalid-request", parsed.error.issues[0]?.message ?? "参数错误")
+  }
+  const checked = commonChecks(parsed.data)
+  if ("error" in checked) return failure(c, 400, "invalid-problem", checked.error)
+  if (checked.sql) return failure(c, 501, "sql-not-supported", SQL_NOT_SUPPORTED)
+
+  const [duplicate] = await db.select({ id: schema.problem.id }).from(schema.problem)
+    .where(and(eq(schema.problem.displayId, parsed.data._id), eq(schema.problem.contestId, contestId))).limit(1)
+  if (duplicate) return failure(c, 409, "display-id-exists", "Duplicate Display id")
+
+  const now = new Date().toISOString()
+  const created = await db.transaction(async (tx) => {
+    const [row] = await tx.insert(schema.problem).values({
+      ...problemValues(parsed.data, false),
+      contestId,
+      createdById: user.id,
+      createTime: now,
+      lastUpdateTime: now,
+      submissionNumber: 0,
+      acceptedNumber: 0,
+      statisticInfo: {},
+      isPublic: false,
+      sqlDisplay: null,
+    }).returning()
+    await setTags(tx as unknown as typeof db, row!.id, parsed.data.tags)
+    return row!
+  })
+  return success(c, await serialize(created), 201)
+})
+
+// ---------------------------------------------------------------- 比赛题 ⇄ 公开题
+
+adminProblemRoutes.post("/problems/:id/make-public", requireProblemPermission, async (c) => {
+  const id = queryInteger(c.req.param("id"), 0, { min: 1 })
+  const parsed = makeProblemPublicRequestSchema.safeParse(await c.req.json().catch(() => null))
+  if (!parsed.success) return failure(c, 400, "invalid-request", "displayId 不能为空")
+
+  const [problem] = await db.select().from(schema.problem).where(eq(schema.problem.id, id)).limit(1)
+  if (!problem) return failure(c, 404, "problem-not-found", "Problem does not exist")
+  if (!problem.contestId || problem.isPublic) {
+    return failure(c, 409, "already-public", "Already be a public problem")
+  }
+  const [duplicate] = await db.select({ id: schema.problem.id }).from(schema.problem)
+    .where(and(eq(schema.problem.displayId, parsed.data.displayId), isNull(schema.problem.contestId))).limit(1)
+  if (duplicate) return failure(c, 409, "display-id-exists", "Duplicate display ID")
+
+  const now = new Date().toISOString()
+  const created = await db.transaction(async (tx) => {
+    // 原比赛题标记成「已转公开」，避免同一道题被转两次
+    await tx.update(schema.problem).set({ isPublic: true }).where(eq(schema.problem.id, id))
+    const { id: _old, ...rest } = problem
+    const [copy] = await tx.insert(schema.problem).values({
+      ...rest,
+      contestId: null,
+      displayId: parsed.data.displayId,
+      // 转出来的公开题默认不可见：题面往往还要按公开场景改一遍
+      visible: false,
+      isPublic: true,
+      submissionNumber: 0,
+      acceptedNumber: 0,
+      statisticInfo: {},
+      createTime: now,
+      lastUpdateTime: now,
+    }).returning()
+    const tags = await tx.select({ tagId: schema.problemTags.problemtagId })
+      .from(schema.problemTags).where(eq(schema.problemTags.problemId, id))
+    if (tags.length) {
+      await tx.insert(schema.problemTags).values(tags.map((tag) => ({
+        problemId: copy!.id, problemtagId: tag.tagId,
+      })))
+    }
+    return copy!
+  })
+  return success(c, await serialize(created), 201)
+})
+
+adminProblemRoutes.post("/contests/:contestId/problems/from-public", requireProblemPermission, async (c) => {
+  const contestId = queryInteger(c.req.param("contestId"), 0, { min: 1 })
+  const parsed = addContestProblemRequestSchema.safeParse(await c.req.json().catch(() => null))
+  if (!parsed.success) {
+    return failure(c, 400, "invalid-request", parsed.error.issues[0]?.message ?? "参数错误")
+  }
+  const [contest] = await db.select().from(schema.contest).where(eq(schema.contest.id, contestId)).limit(1)
+  const [problem] = await db.select().from(schema.problem)
+    .where(eq(schema.problem.id, parsed.data.problemId)).limit(1)
+  if (!contest || !problem) return failure(c, 404, "not-found", "Contest or Problem does not exist")
+  const user = c.get("user")!
+  if (user.adminType !== "Super Admin" && contest.createdById !== user.id) {
+    return failure(c, 404, "contest-not-found", "Contest does not exist")
+  }
+  if (contestStatus(contest) === "-1") return failure(c, 409, "contest-ended", "Contest has ended")
+
+  const [duplicate] = await db.select({ id: schema.problem.id }).from(schema.problem)
+    .where(and(eq(schema.problem.contestId, contestId), eq(schema.problem.displayId, parsed.data.displayId))).limit(1)
+  if (duplicate) return failure(c, 409, "display-id-exists", "Duplicate display id in this contest")
+
+  const now = new Date().toISOString()
+  const created = await db.transaction(async (tx) => {
+    const { id: _old, ...rest } = problem
+    const [copy] = await tx.insert(schema.problem).values({
+      ...rest,
+      contestId,
+      isPublic: true,
+      visible: true,
+      displayId: parsed.data.displayId,
+      submissionNumber: 0,
+      acceptedNumber: 0,
+      statisticInfo: {},
+      createTime: now,
+      lastUpdateTime: now,
+    }).returning()
+    const tags = await tx.select({ tagId: schema.problemTags.problemtagId })
+      .from(schema.problemTags).where(eq(schema.problemTags.problemId, problem.id))
+    if (tags.length) {
+      await tx.insert(schema.problemTags).values(tags.map((tag) => ({
+        problemId: copy!.id, problemtagId: tag.tagId,
+      })))
+    }
+    return copy!
+  })
+  return success(c, await serialize(created), 201)
+})
diff --git a/apps/web/src/admin/api.ts b/apps/web/src/admin/api.ts
index 9efb238..bfc4179 100644
--- a/apps/web/src/admin/api.ts
+++ b/apps/web/src/admin/api.ts
@@ -38,21 +38,13 @@ export async function getProblemList(
   contestID?: string,
   tagId?: number,
 ) {
-  const endpoint = !!contestID ? "admin/contest/problem" : "admin/problem"
-  const res = await http.get<{ results: AdminProblem[]; total: number }>(
-    endpoint,
-    {
-      params: {
-        paging: true,
-        offset,
-        limit,
-        keyword,
-        author,
-        contest_id: contestID,
-        tag_id: tagId,
-      },
-    },
-  )
+  const endpoint = contestID
+    ? `admin/contests/${contestID}/problems`
+    : "admin/problems"
+  const res = await legacyResponse<{
+    results: AdminProblem[]
+    total: number
+  }>(api2.get(endpoint, { params: { offset, limit, keyword, author, tagId } }))
   return {
     results: res.data.results.map(toProblemListItem),
     total: res.data.total,
@@ -60,15 +52,21 @@ export async function getProblemList(
 }
 
 export function deleteProblem(id: number) {
-  return http.delete("admin/problem", { params: { id } })
+  return api2.delete(`admin/problems/${id}`)
 }
 
+// 比赛题与公开题共用一条删除路由，比赛由后端从题目推导
 export function deleteContestProblem(id: number) {
-  return http.delete("admin/contest/problem", { params: { id } })
+  return api2.delete(`admin/problems/${id}`)
 }
 
 export function editProblem(problem: AdminProblem | BlankProblem) {
-  return http.put("admin/problem", problem)
+  return legacyResponse(
+    api2.put(
+      `admin/problems/${(problem as AdminProblem).id}`,
+      toProblemBody(problem),
+    ),
+  )
 }
 
 export function toggleProblemVisible(problemID: number) {
@@ -80,15 +78,20 @@ export function generateFlowchartFromPythonCode(python: string) {
 }
 
 export function editContestProblem(problem: AdminProblem | BlankProblem) {
-  return http.put("admin/contest/problem", problem)
+  return legacyResponse(
+    api2.put(
+      `admin/problems/${(problem as AdminProblem).id}`,
+      toProblemBody(problem),
+    ),
+  )
 }
 
 export function getProblem(id: string | number) {
-  return http.get<AdminProblem>("admin/problem", { params: { id } })
+  return legacyResponse<AdminProblem>(api2.get(`admin/problems/${id}`))
 }
 
 export function getContestProblem(id: number) {
-  return http.get("admin/contest/problem", { params: { id } })
+  return legacyResponse<AdminProblem>(api2.get(`admin/problems/${id}`))
 }
 
 // 标签管理
@@ -239,12 +242,49 @@ export function generateSQLTestcase(data: {
   return http.post<{ sql: string }>("admin/sql_test_case_ai_gen", data)
 }
 
+/** 组件里的题目对象是 snake_case，出站转成新后端要的 camelCase */
+function toProblemBody(problem: AdminProblem | BlankProblem) {
+  const p = problem as Record<string, any>
+  return {
+    _id: p._id,
+    title: p.title,
+    description: p.description,
+    inputDescription: p.input_description ?? "",
+    outputDescription: p.output_description ?? "",
+    samples: p.samples ?? [],
+    testCaseId: p.test_case_id,
+    testCaseScore: p.test_case_score ?? [],
+    timeLimit: p.time_limit,
+    memoryLimit: p.memory_limit,
+    languages: p.languages ?? [],
+    template: p.template ?? {},
+    visible: p.visible,
+    difficulty: p.difficulty,
+    tags: p.tags ?? [],
+    hint: p.hint ?? null,
+    source: p.source ?? null,
+    prompt: p.prompt ?? null,
+    answers: p.answers ?? [],
+    shareSubmission: p.share_submission ?? false,
+    allowFlowchart: p.allow_flowchart ?? false,
+    showFlowchart: p.show_flowchart ?? false,
+    mermaidCode: p.mermaid_code ?? null,
+    flowchartHint: p.flowchart_hint ?? null,
+    astRules: p.ast_rules ?? null,
+    sqlConfig: p.sql_config ?? null,
+  }
+}
+
 export function createProblem(problem: BlankProblem) {
-  return http.post("admin/problem", problem)
+  return legacyResponse(api2.post("admin/problems", toProblemBody(problem)))
 }
 
 export function createContestProblem(problem: BlankProblem) {
-  return http.post("admin/contest/problem", problem)
+  // contest_id 由 detail.vue 在提交前写进 problem 对象
+  const contestID = (problem as Record<string, any>).contest_id
+  return legacyResponse(
+    api2.post(`admin/contests/${contestID}/problems`, toProblemBody(problem)),
+  )
 }
 
 /** 组件里的比赛对象是 snake_case，出站转成新后端要的 camelCase */
@@ -289,11 +329,12 @@ export function addProblemForContest(
   problemID: number,
   displayID: string,
 ) {
-  return http.post("admin/contest/add_problem_from_public", {
-    contest_id: contestID,
-    problem_id: problemID,
-    display_id: displayID,
-  })
+  return legacyResponse(
+    api2.post(`admin/contests/${contestID}/problems/from-public`, {
+      problemId: problemID,
+      displayId: displayID,
+    }),
+  )
 }
 
 export function getWebsite() {
@@ -451,10 +492,9 @@ export function deleteExercise(id: number) {
 
 // 将竞赛题目转为公开题目
 export function makeProblemPublic(id: number, display_id: string) {
-  return http.post("admin/contest_problem/make_public", {
-    id,
-    display_id,
-  })
+  return legacyResponse(
+    api2.post(`admin/problems/${id}/make-public`, { displayId: display_id }),
+  )
 }
 
 // 比赛辅助检查
diff --git a/packages/contract/src/admin.ts b/packages/contract/src/admin.ts
index 0a92862..138a2be 100644
--- a/packages/contract/src/admin.ts
+++ b/packages/contract/src/admin.ts
@@ -487,3 +487,102 @@ export const acTrendSchema = z.object({
 
 export const generateFlowchartRequestSchema = z.object({ python: z.string().min(1).max(64 * 1024) })
 export const generateFlowchartResponseSchema = z.object({ flowchart: z.string() })
+
+// ---------------------------------------------------------------- 题目管理
+
+export const adminProblemListItemSchema = z.object({
+  id: z.number().int(),
+  _id: z.string(),
+  title: z.string(),
+  createdBy: sampleUserSchema,
+  visible: z.boolean(),
+  createTime: z.string(),
+  difficulty: z.string(),
+  tags: z.array(z.string()),
+  hasAstRules: z.boolean(),
+  allowFlowchart: z.boolean(),
+  showFlowchart: z.boolean(),
+  topReaction: z.string().nullable(),
+})
+
+export const adminProblemListSchema = paginatedSchema(adminProblemListItemSchema)
+
+/** 后台题目详情：包含 oj 侧永不下发的 answers / testCase* / astRules */
+export const adminProblemSchema = z.object({
+  id: z.number().int(),
+  _id: z.string(),
+  title: z.string(),
+  description: z.string(),
+  inputDescription: z.string(),
+  outputDescription: z.string(),
+  samples: z.array(z.record(z.string(), z.unknown())),
+  testCaseId: z.string(),
+  testCaseScore: z.array(z.record(z.string(), z.unknown())),
+  hint: z.string().nullable(),
+  languages: z.array(z.string()),
+  template: z.record(z.string(), z.string()),
+  createTime: z.string(),
+  lastUpdateTime: z.string(),
+  timeLimit: z.number().int(),
+  memoryLimit: z.number().int(),
+  visible: z.boolean(),
+  difficulty: z.string(),
+  source: z.string().nullable(),
+  submissionNumber: z.number().int(),
+  acceptedNumber: z.number().int(),
+  statisticInfo: z.record(z.string(), z.unknown()),
+  shareSubmission: z.boolean(),
+  contestId: z.number().int().nullable(),
+  createdBy: sampleUserSchema,
+  isPublic: z.boolean(),
+  tags: z.array(z.string()),
+  allowFlowchart: z.boolean(),
+  showFlowchart: z.boolean(),
+  mermaidCode: z.string().nullable(),
+  flowchartHint: z.string().nullable(),
+  astRules: z.unknown(),
+  answers: z.array(z.record(z.string(), z.unknown())),
+  prompt: z.string().nullable(),
+  sqlConfig: z.record(z.string(), z.unknown()).nullable(),
+  sqlDisplay: z.record(z.string(), z.unknown()).nullable(),
+})
+
+export const createProblemRequestSchema = z.object({
+  _id: z.string().trim().min(1).max(32),
+  title: z.string().trim().min(1).max(1024),
+  description: z.string(),
+  inputDescription: z.string(),
+  outputDescription: z.string(),
+  samples: z.array(z.record(z.string(), z.unknown())),
+  testCaseId: z.string().regex(/^[a-zA-Z0-9]+$/).max(32),
+  testCaseScore: z.array(z.record(z.string(), z.unknown())),
+  timeLimit: z.number().int().min(1).max(1000 * 60),
+  memoryLimit: z.number().int().min(1).max(1024),
+  languages: z.array(z.string()).min(1),
+  template: z.record(z.string(), z.string()),
+  visible: z.boolean(),
+  difficulty: z.enum(["Low", "Mid", "High"]),
+  tags: z.array(z.string().max(32)).min(1),
+  hint: z.string().nullable().default(null),
+  source: z.string().max(256).nullable().default(null),
+  prompt: z.string().nullable().default(null),
+  answers: z.array(z.record(z.string(), z.unknown())).default([]),
+  shareSubmission: z.boolean(),
+  allowFlowchart: z.boolean().default(false),
+  showFlowchart: z.boolean().default(false),
+  mermaidCode: z.string().nullable().default(null),
+  flowchartHint: z.string().nullable().default(null),
+  astRules: z.unknown().default(null),
+  sqlConfig: z.record(z.string(), z.unknown()).nullable().default(null),
+})
+
+export const updateProblemRequestSchema = createProblemRequestSchema
+
+export const makeProblemPublicRequestSchema = z.object({
+  displayId: z.string().trim().min(1).max(32),
+})
+
+export const addContestProblemRequestSchema = z.object({
+  problemId: z.number().int().positive(),
+  displayId: z.string().trim().min(1).max(32),
+})