diff --git a/CLAUDE.md b/CLAUDE.md
index beead18..16343d3 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -102,6 +102,33 @@ dev 直接起不来。
 这些整数是**落库的值**：12 万条历史提交的 `submission.result` 就是它们，判题沙箱回的也是
 这套编码，所以只能新增、不能改已有的含义。题目表情 reaction 的语义 key 同理。
 
+### AST 代码规则有两张表，必须同增同减
+
+契约的 `AST_NODE_TARGETS_BY_LANGUAGE`（target → 中文名）决定后台下拉能选什么，
+`apps/api/src/judge/ast.ts` 的 `mappings`（target → tree-sitter 节点类型）决定判题机
+认得什么。**加节点类型时两边都要加**，运算符表 `AST_OPERATOR_TARGETS_BY_LANGUAGE` 同理。
+
+只加一边是**静默错判**：判题机 `mapping[target] ?? target` 拿裸名去比节点类型，
+C 的语法树里永远不存在 `list_comprehension`，于是「必须使用列表推导式」永远失败、
+「不能使用 f-string」永远通过，两头都不报错，只有学生受着。原来那张表是 C/Python
+混在一起的 15 条，整份铺成下拉，给 C 题也能选到 Python 专有节点——就是这么来的。
+
+判题机只认 `AST_SUPPORTED_LANGUAGES` 里的语言（C / C++ / Python3）。别的语言配了规则
+一条都不会跑，所以后台不给它们开 tab，题目页也不把它们的规则展示成「要求」——
+**看得见却不检查**比没有更糟。
+
+C++ 的语法表是「C 的全集 + C++ 独有的几条」，因为 tree-sitter-cpp 继承 tree-sitter-c，
+C 那 14 个 target 在 C++ 树里逐个实测通用。但**调用形态两者不同**，加语言时必须一起看：
+`a.push_back()` 和 `p->push_back()` 在 C++ 都是 `call_expression` + `field_expression`，
+不是 Python 的 `attribute`；`std::sort(...)` 的 function 是 `qualified_identifier`
+而不是 `identifier`，所以 `functionCalls` 对 C++ 额外比一次 `::` 末段——否则学生写了
+`using namespace std` 与否会得到不同的判定结果。
+
+规则的语义校验在 `astRulesError()`，不在 zod 的 refine 上：`astRulesSchema` 同时用于
+**读**后台题目详情，在读路径上抛错会让历史脏数据把整个题目详情打不开。同理，保存前
+先 `pickAstRules()` 剔除够不着的分组再校验，否则早年配过 C++ 规则的题会把老师锁死
+——tab 里看不到那组规则，保存却被拦下。
+
 ### 比赛只有 ACM 模式
 
 没有 OI。上一代残留的 OI 分支在阶段 0 已经砍掉，不要"顺手补回来"。
diff --git a/apps/api/package.json b/apps/api/package.json
index 205d1ea..1e65b23 100644
--- a/apps/api/package.json
+++ b/apps/api/package.json
@@ -29,6 +29,7 @@
     "postgres": "^3.4.9",
     "sql.js": "^1.14.2",
     "tree-sitter-c": "^0.24.1",
+    "tree-sitter-cpp": "^0.23.4",
     "tree-sitter-python": "^0.25.0",
     "web-tree-sitter": "^0.26.13",
     "zod": "^4.4.3"
diff --git a/apps/api/src/judge/ast.ts b/apps/api/src/judge/ast.ts
index f245ea7..1d69f70 100644
--- a/apps/api/src/judge/ast.ts
+++ b/apps/api/src/judge/ast.ts
@@ -1,14 +1,21 @@
 import {
+  AST_NODE_TARGETS_BY_LANGUAGE,
+  AST_OPERATOR_TARGETS_BY_LANGUAGE,
+  astNodeLabel,
+  astOperatorLabel,
+  astRuleIsMeaningful,
   astRuleSchema,
-  AST_NODE_TARGET_LABELS,
+  AST_SUPPORTED_LANGUAGES,
   type AstRequirement,
   type AstRequirements,
   type AstRule,
+  type AstRules,
 } from "@oj2/contract"
 import { Language, Parser, type Node } from "web-tree-sitter"
 // 语法 wasm 内嵌成资源。原来是 `Bun.resolveSync(pkg + "/" + name, import.meta.dir)`，
 // 编译成单二进制后 import.meta.dir 是 /$bunfs/root，解析不到 node_modules。见 vendor/jieba.ts
 import cWasmPath from "tree-sitter-c/tree-sitter-c.wasm" with { type: "file" }
+import cppWasmPath from "tree-sitter-cpp/tree-sitter-cpp.wasm" with { type: "file" }
 import pythonWasmPath from "tree-sitter-python/tree-sitter-python.wasm" with { type: "file" }
 // web-tree-sitter 自己的运行时 wasm，Parser.init() 要用
 import treeSitterWasmPath from "web-tree-sitter/web-tree-sitter.wasm" with { type: "file" }
@@ -20,8 +27,17 @@ export type { AstRule } from "@oj2/contract"
 export interface AstResult {
   description: string
   passed: boolean
+  /** count_* 引擎实际数到的次数。失败时前端拿它补一句「当前 N 次」 */
+  actual?: number
 }
 
+/**
+ * target → tree-sitter 节点类型。恒等的条目（`+`、`==` 这些运算符）不列，
+ * 走 `mapping[target] ?? target` 回落。
+ *
+ * **这里的键集是契约 AST_NODE_TARGETS_BY_LANGUAGE 的另一半**，两边必须同增同减：
+ * 那边决定后台下拉能选什么，这边决定判题机认得什么。只加一边就是静默错判。
+ */
 const mappings: Record<string, Record<string, string>> = {
   C: {
     for_loop: "for_statement",
@@ -42,6 +58,35 @@ const mappings: Record<string, Record<string, string>> = {
     or: "||",
     not: "!",
   },
+  "C++": {
+    // C 的那 14 条原样通用（tree-sitter-cpp 继承 tree-sitter-c 的语法）
+    for_loop: "for_statement",
+    while_loop: "while_statement",
+    do_while: "do_statement",
+    if_statement: "if_statement",
+    else_clause: "else_clause",
+    break: "break_statement",
+    continue: "continue_statement",
+    function_definition: "function_definition",
+    return: "return_statement",
+    switch_statement: "switch_statement",
+    case_statement: "case_statement",
+    assignment: "assignment_expression",
+    struct: "struct_specifier",
+    include: "preproc_include",
+    // C++ 独有
+    range_for_loop: "for_range_loop",
+    class_definition: "class_specifier",
+    try_except: "try_statement",
+    throw: "throw_statement",
+    namespace: "namespace_definition",
+    template: "template_declaration",
+    lambda: "lambda_expression",
+    using: "using_declaration",
+    and: "&&",
+    or: "||",
+    not: "!",
+  },
   Python3: {
     for_loop: "for_statement",
     while_loop: "while_statement",
@@ -79,7 +124,12 @@ async function loadLanguage(language: string) {
   const cached = languages.get(language)
   if (cached) return cached
 
-  const loaded = await Language.load(language === "C" ? cWasmPath : pythonWasmPath)
+  const wasmPath = language === "C"
+    ? cWasmPath
+    : language === "C++"
+      ? cppWasmPath
+      : pythonWasmPath
+  const loaded = await Language.load(wasmPath)
   languages.set(language, loaded)
   return loaded
 }
@@ -95,9 +145,9 @@ function hasNode(root: Node, type: string): boolean {
   return root.children.some((child) => hasNode(child, type))
 }
 
-function targetName(rule: AstRule) {
+function targetName(rule: AstRule, language?: string) {
   const target = rule.target ?? ""
-  return rule.label || AST_NODE_TARGET_LABELS[target] || target || "指定语法"
+  return rule.label || astNodeLabel(target, language) || "指定语法"
 }
 
 function countPhrase(verb: string, rule: AstRule) {
@@ -114,9 +164,9 @@ function countPhrase(verb: string, rule: AstRule) {
  * 用的是同一份 —— 原来前端 ProblemContent.vue 里另有一份几乎一样的实现，
  * 只有 min/max 同时给出时的措辞不一样（生产库里没有这种规则）。
  */
-export function describeAstRule(rule: AstRule): string {
+export function describeAstRule(rule: AstRule, language?: string): string {
   if (rule.message) return rule.message
-  const name = targetName(rule)
+  const name = targetName(rule, language)
   const target = rule.target ?? ""
   switch (rule.engine) {
     case "must_exist_node":
@@ -136,10 +186,12 @@ export function describeAstRule(rule: AstRule): string {
     case "must_not_call_method":
       return `不能调用 .${target}()`
     case "must_use_operator":
-      return `必须使用 ${target} 运算符`
+      return `必须使用 ${astOperatorLabel(target, language)} 运算符`
     case "must_have_nesting": {
-      const outer = rule.outer ?? ""
-      const inner = rule.inner ?? ""
+      // 这两个走 astNodeLabel 而不是裸值 —— 少了这一步文案就是
+      // 「必须使用 for_loop 嵌套」，旧栈 ast_checker/engines/nesting.py 是翻的
+      const outer = astNodeLabel(rule.outer ?? "", language)
+      const inner = astNodeLabel(rule.inner ?? "", language)
       return outer === inner
         ? `必须使用 ${outer} 嵌套`
         : `必须在 ${outer} 中嵌套使用 ${inner}`
@@ -157,6 +209,10 @@ function requirementKind(engine: AstRule["engine"]): AstRequirement["kind"] {
 /**
  * 把规则原文投影成下发给学生的「代码要求」。规则里的 engine / target 不出现在
  * 响应里 —— 阶段 3 泄露评审收掉 ast_rules 时要的就是这个，见契约的注释。
+ *
+ * 只投影判题机真检查得了的语言。原来这里不看语言，给 C++ 题配的规则照样渲染成
+ * 「必须使用 for 循环」挂在题目页上，而 loadLanguage 对 C++ 返回 null、
+ * checkAst 直接放行 —— 学生看得见要求，判题从不检查。
  */
 export function astRequirements(value: unknown): AstRequirements | null {
   const grouped = value && typeof value === "object" && !Array.isArray(value)
@@ -166,11 +222,13 @@ export function astRequirements(value: unknown): AstRequirements | null {
   const out: AstRequirements = {}
   for (const [language, rules] of Object.entries(grouped)) {
     if (!Array.isArray(rules)) continue
+    if (!AST_SUPPORTED_LANGUAGES.includes(language)) continue
     const items = rules.flatMap((rule) => {
       const parsed = astRuleSchema.safeParse(rule)
       if (!parsed.success) return []
+      if (!astRuleIsMeaningful(parsed.data)) return []
       return [{
-        description: describeAstRule(parsed.data),
+        description: describeAstRule(parsed.data, language),
         kind: requirementKind(parsed.data.engine),
       }]
     })
@@ -179,6 +237,63 @@ export function astRequirements(value: unknown): AstRequirements | null {
   return Object.keys(out).length > 0 ? out : null
 }
 
+/**
+ * AST 规则的语义校验。zod 只管形状（engine 在枚举里、min 是整数），管不了
+ * 「给 C 题选了只有 Python 才有的 list_comprehension」这类组合 —— 那种规则存得进去，
+ * 判题时 `mapping[target] ?? target` 拿裸名去比节点类型，永远失败或永远通过，
+ * 两头都不报错，只有学生受着。
+ *
+ * 放这儿而不是 astRulesSchema 的 refine 上：那个 schema 同时用于**读**后台题目详情，
+ * 在读路径上抛错会让历史脏数据直接把题目详情打不开。
+ */
+export function astRulesError(astRules: AstRules | null): string | null {
+  if (!astRules) return null
+  for (const [language, rules] of Object.entries(astRules)) {
+    if (rules.length === 0) continue
+    if (!AST_SUPPORTED_LANGUAGES.includes(language)) {
+      return `代码规则暂不支持 ${language}，判题机只检查 ${AST_SUPPORTED_LANGUAGES.join(" / ")}`
+    }
+    const nodes = AST_NODE_TARGETS_BY_LANGUAGE[language] ?? {}
+    const operators = AST_OPERATOR_TARGETS_BY_LANGUAGE[language] ?? {}
+    for (const [index, rule] of rules.entries()) {
+      const at = `代码规则 ${language} 第 ${index + 1} 条`
+      const target = rule.target ?? ""
+      if (rule.engine.endsWith("_node")) {
+        if (!(target in nodes)) return `${at}：${language} 没有「${target}」这种语法`
+      } else if (rule.engine === "must_use_operator") {
+        if (!(target in operators)) return `${at}：${language} 没有「${target}」运算符`
+      } else if (rule.engine === "must_have_nesting") {
+        for (const value of [rule.outer ?? "", rule.inner ?? ""]) {
+          if (!(value in nodes)) return `${at}：${language} 没有「${value}」这种语法`
+        }
+      } else if (!target.trim()) {
+        return `${at}：要检查的函数名/方法名不能为空`
+      }
+      if (!astRuleIsMeaningful(rule)) return `${at}：次数检查至少要填一个数字`
+    }
+  }
+  return null
+}
+
+/**
+ * 保存前清掉够不着的规则分组：不在题目 languages 里的（老师改过语言列表），
+ * 以及判题机检查不了的（C++ / Java / …）。两者编辑器都不给开 tab，留着就是死数据。
+ *
+ * 必须先剔除再校验，否则历史脏数据会把老师锁死：一道 languages 含 C++ 的题，
+ * 早年配过 C++ 规则，如今 tab 里看不到那组规则，保存却被「暂不支持 C++」拦下，
+ * 老师在界面上无从修改。
+ */
+export function pickAstRules(astRules: AstRules | null, languages: string[]): AstRules | null {
+  if (!astRules) return null
+  const out: AstRules = {}
+  for (const [language, rules] of Object.entries(astRules)) {
+    if (!languages.includes(language)) continue
+    if (!AST_SUPPORTED_LANGUAGES.includes(language)) continue
+    if (rules.length > 0) out[language] = rules
+  }
+  return Object.keys(out).length > 0 ? out : null
+}
+
 function rangePassed(count: number, rule: AstRule) {
   if (rule.exact !== undefined && count !== rule.exact) return false
   if (rule.min !== undefined && count < rule.min) return false
@@ -186,16 +301,41 @@ function rangePassed(count: number, rule: AstRule) {
   return true
 }
 
+const CALL_NODE_TYPES: Record<string, string> = {
+  C: "call_expression",
+  "C++": "call_expression",
+  Python3: "call",
+}
+
 function functionCalls(root: Node, target: string, language: string) {
-  const callType = language === "C" ? "call_expression" : "call"
+  const callType = CALL_NODE_TYPES[language] ?? "call"
   return collectNodes(root, callType).filter((call) => {
     const fn = call.childForFieldName("function")
-    return fn?.type === "identifier" && fn.text === target
+    if (!fn) return false
+    if (fn.type === "identifier") return fn.text === target
+    // `std::sort(...)` 是 qualified_identifier。学生写 sort 还是 std::sort 取决于
+    // 有没有 using namespace std，两种都得认，所以末段也比一次
+    if (language === "C++" && fn.type === "qualified_identifier") {
+      return fn.text === target || fn.text.split("::").pop() === target
+    }
+    return false
   })
 }
 
 function methodCalls(root: Node, target: string, language: string) {
-  if (language === "C") return []
+  // C++ 的 `a.push_back()` / `p->push_back()` 都是 call_expression + field_expression，
+  // 和 Python 的 attribute 不是一回事 —— 少了这个分支，C++ 的「必须调用 .push_back()」
+  // 会静默地永远失败
+  if (language === "C++") {
+    return collectNodes(root, "call_expression").filter((call) => {
+      const fn = call.childForFieldName("function")
+      return (
+        fn?.type === "field_expression" &&
+        fn.childForFieldName("field")?.text === target
+      )
+    })
+  }
+  if (language !== "Python3") return []
   return collectNodes(root, "call").filter((call) => {
     const fn = call.childForFieldName("function")
     return (
@@ -217,51 +357,53 @@ function evaluateRule(
   switch (rule.engine) {
     case "must_exist_node":
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: hasNode(root, nodeType),
       }
     case "must_not_exist_node":
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: !hasNode(root, nodeType),
       }
     case "count_node": {
       const count = collectNodes(root, nodeType).length
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: rangePassed(count, rule),
+        actual: count,
       }
     }
     case "must_call_function":
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: functionCalls(root, target, language).length > 0,
       }
     case "must_not_call_function":
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: functionCalls(root, target, language).length === 0,
       }
     case "count_function_call": {
       const count = functionCalls(root, target, language).length
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: rangePassed(count, rule),
+        actual: count,
       }
     }
     case "must_call_method":
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: methodCalls(root, target, language).length > 0,
       }
     case "must_not_call_method":
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: methodCalls(root, target, language).length === 0,
       }
     case "must_use_operator":
       return {
-        description: describeAstRule(rule),
+        description: describeAstRule(rule, language),
         passed: hasNode(root, nodeType),
       }
     case "must_have_nesting": {
@@ -272,7 +414,7 @@ function evaluateRule(
       const passed = collectNodes(root, outerType).some((node) =>
         node.children.some((child) => hasNode(child, innerType)),
       )
-      return { description: describeAstRule(rule), passed }
+      return { description: describeAstRule(rule, language), passed }
     }
     default:
       return null
@@ -297,6 +439,7 @@ export async function checkAst(
     try {
       const mapping = mappings[language] ?? {}
       const results = rules
+        .filter(astRuleIsMeaningful)
         .map((rule) => evaluateRule(tree.rootNode, rule, language, mapping))
         .filter((result): result is AstResult => result !== null)
       return { passed: results.every((result) => result.passed), results }
diff --git a/apps/api/src/routes/admin/problem.ts b/apps/api/src/routes/admin/problem.ts
index 041ffb3..6eb1978 100644
--- a/apps/api/src/routes/admin/problem.ts
+++ b/apps/api/src/routes/admin/problem.ts
@@ -11,6 +11,7 @@ import {
   sqlPreviewRequestSchema,
   sqlTestCaseScriptSchema,
   uploadTestCaseResponseSchema,
+  type AstRules,
   type SqlConfig,
 } from "@oj2/contract"
 import { and, count, desc, eq, ilike, inArray, isNull, ne, or, sql } from "drizzle-orm"
@@ -20,6 +21,7 @@ import { requireProblemPermission, type AppEnv } from "../../auth/middleware"
 import type { AuthUser } from "../../auth/session"
 import { db, schema } from "../../db"
 import { failure, success } from "../../http"
+import { astRulesError, pickAstRules } from "../../judge/ast"
 import { buildSqlDisplay } from "../../judge/sql"
 import { completeChat } from "../../services/ai"
 import { contestStatus } from "../../services/contest"
@@ -176,7 +178,10 @@ function commonChecks(data: {
   samples: unknown[]
   sqlConfig: SqlConfig | null
   answers: Record<string, unknown>[]
+  astRules: AstRules | null
 }): { error: string } | { sql: boolean } {
+  const astError = astRulesError(pickAstRules(data.astRules, data.languages))
+  if (astError) return { error: astError }
   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" }
@@ -247,7 +252,7 @@ function problemValues(data: ReturnType<typeof createProblemRequestSchema.parse>
     showFlowchart: data.showFlowchart,
     mermaidCode: data.mermaidCode,
     flowchartHint: data.flowchartHint,
-    astRules: data.astRules ?? null,
+    astRules: pickAstRules(data.astRules, data.languages),
     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
diff --git a/apps/web/src/admin/problem/components/AstRulesEditor.vue b/apps/web/src/admin/problem/components/AstRulesEditor.vue
index 7268d4e..d051101 100644
--- a/apps/web/src/admin/problem/components/AstRulesEditor.vue
+++ b/apps/web/src/admin/problem/components/AstRulesEditor.vue
@@ -1,5 +1,9 @@
 <script setup lang="ts">
-import { AST_NODE_TARGET_LABELS } from "@oj2/contract"
+import {
+  AST_NODE_TARGETS_BY_LANGUAGE,
+  AST_OPERATOR_TARGETS_BY_LANGUAGE,
+  AST_SUPPORTED_LANGUAGES,
+} from "@oj2/contract"
 import type { AstRule, AstRules, LANGUAGE } from "utils/types"
 
 interface Props {
@@ -12,7 +16,17 @@ const emit = defineEmits<{
   (e: "update:modelValue", value: AstRules | null): void
 }>()
 
-const activeTab = ref(props.languages[0] || "Python3")
+// 判题机只认 C / Python3，别的语言配了规则也一条都不会跑（judge/ast.ts 的
+// loadLanguage 返回 null 就直接放行）。原来这里按题目的全部语言开 tab，老师给
+// C++ 配的规则存得下、题目页也照常显示成「要求」，判题却从不检查。
+const supportedLanguages = computed(() =>
+  props.languages.filter((lang) => AST_SUPPORTED_LANGUAGES.includes(lang)),
+)
+const unsupportedLanguages = computed(() =>
+  props.languages.filter((lang) => !AST_SUPPORTED_LANGUAGES.includes(lang)),
+)
+
+const activeTab = ref(supportedLanguages.value[0] || "Python3")
 
 const ENGINE_OPTIONS: SelectOption[] = [
   {
@@ -52,32 +66,21 @@ const ENGINE_OPTIONS: SelectOption[] = [
   },
 ]
 
-// 选项从契约的 AST_NODE_TARGET_LABELS 生成 —— 这 15 条原来在这里和
-// ProblemContent.vue 各手抄一份
-const NODE_TARGET_OPTIONS: SelectOption[] = Object.entries(
-  AST_NODE_TARGET_LABELS,
-).map(([value, label]) => ({ label, value }))
+// 选项按语言生成。原来是一张 C/Python 混合的 15 条表整份铺开，给 C 题也能选到
+// 列表推导式、f-string 这些 C 根本没有的东西 —— 存得进去，判题时永远失败
+// （或者反过来，「不能使用 f-string」永远通过），两头都不报错。
+function nodeTargetOptions(lang: string): SelectOption[] {
+  return Object.entries(AST_NODE_TARGETS_BY_LANGUAGE[lang] ?? {}).map(
+    ([value, label]) => ({ label, value }),
+  )
+}
 
-const OPERATOR_TARGET_OPTIONS: SelectOption[] = [
-  { label: "+", value: "+" },
-  { label: "-", value: "-" },
-  { label: "*", value: "*" },
-  { label: "/", value: "/" },
-  { label: "//", value: "//" },
-  { label: "%", value: "%" },
-  { label: "**", value: "**" },
-  { label: "+=", value: "+=" },
-  { label: "-=", value: "-=" },
-  { label: "==", value: "==" },
-  { label: "!=", value: "!=" },
-  { label: ">", value: ">" },
-  { label: ">=", value: ">=" },
-  { label: "<", value: "<" },
-  { label: "<=", value: "<=" },
-  { label: "and / &&", value: "and" },
-  { label: "or / ||", value: "or" },
-  { label: "not / !", value: "not" },
-]
+// 逻辑名 and/or/not 在 C 里显示成 && / || / !，存进去的还是逻辑名
+function operatorTargetOptions(lang: string): SelectOption[] {
+  return Object.entries(AST_OPERATOR_TARGETS_BY_LANGUAGE[lang] ?? {}).map(
+    ([value, label]) => ({ label: label === value ? value : `${label}（${value}）`, value }),
+  )
+}
 
 const NODE_ENGINES = ["must_exist_node", "must_not_exist_node", "count_node"]
 const FUNCTION_ENGINES = [
@@ -122,6 +125,9 @@ function updateCountMode(lang: string, index: number, mode: "exact" | "range") {
     delete rule.min
     delete rule.max
   } else {
+    // 留空的 count 规则恒真（rangePassed 三个字段全 undefined 就返回 true），
+    // 描述还会退化成光秃秃一个「for 循环」。切过来先给个 1
+    rule.min = rule.min ?? 1
     delete rule.exact
   }
   rules[index] = rule
@@ -162,12 +168,14 @@ function updateRules(lang: string, rules: AstRule[]) {
   emit("update:modelValue", Object.keys(current).length > 0 ? current : null)
 }
 
-function getTargetLabel(engine: string, target: string): string | undefined {
-  if (isNodeEngine(engine))
-    return (NODE_TARGET_OPTIONS.find((o) => o.value === target) as any)?.label
-  if (isOperatorEngine(engine))
-    return (OPERATOR_TARGET_OPTIONS.find((o) => o.value === target) as any)
-      ?.label
+function getTargetLabel(
+  lang: string,
+  engine: string,
+  target: string,
+): string | undefined {
+  if (isNodeEngine(engine)) return AST_NODE_TARGETS_BY_LANGUAGE[lang]?.[target]
+  // 运算符不写 label：判题结果的文案按语言翻译（astOperatorLabel），
+  // 存一个固定 label 反而会把 C 的 && 钉死成 and
   return undefined
 }
 
@@ -176,7 +184,7 @@ function addRule(lang: string) {
   rules.push({
     engine: "must_exist_node",
     target: "for_loop",
-    label: "for 循环",
+    label: getTargetLabel(lang, "must_exist_node", "for_loop"),
     message: "",
   })
   updateRules(lang, rules)
@@ -196,10 +204,10 @@ function updateRule(lang: string, index: number, field: string, value: any) {
     rule.engine = value
     if (isNodeEngine(value)) {
       rule.target = "for_loop"
-      rule.label = "for 循环"
+      rule.label = getTargetLabel(lang, value, "for_loop")
     } else if (isOperatorEngine(value)) {
       rule.target = "+"
-      rule.label = "+"
+      delete rule.label
     } else {
       rule.target = ""
       delete rule.label
@@ -207,9 +215,11 @@ function updateRule(lang: string, index: number, field: string, value: any) {
     delete rule.min
     delete rule.max
     delete rule.exact
+    // 次数引擎不给默认值的话，存下去就是一条恒真规则
+    if (isCountEngine(value)) rule.exact = 1
   } else if (field === "target") {
     rule.target = value
-    const lbl = getTargetLabel(rule.engine, value)
+    const lbl = getTargetLabel(lang, rule.engine, value)
     if (lbl) rule.label = lbl
     else delete rule.label
   } else if (field === "min") {
@@ -226,22 +236,32 @@ function updateRule(lang: string, index: number, field: string, value: any) {
   updateRules(lang, rules)
 }
 
-watch(
-  () => props.languages,
-  (langs) => {
-    if (langs.length && !langs.includes(activeTab.value as LANGUAGE)) {
-      activeTab.value = langs[0]
-    }
-  },
-)
+watch(supportedLanguages, (langs) => {
+  if (langs.length && !langs.includes(activeTab.value as LANGUAGE)) {
+    activeTab.value = langs[0]
+  }
+})
 </script>
 
 <template>
   <n-collapse>
     <n-collapse-item title="代码规则检查（选填）" name="ast-rules">
-      <n-tabs v-if="languages.length" type="segment" v-model:value="activeTab">
+      <n-alert
+        v-if="unsupportedLanguages.length"
+        type="info"
+        :bordered="false"
+        style="margin-bottom: 8px"
+      >
+        {{ unsupportedLanguages.join("、") }} 暂不支持代码规则检查，判题机只能检查
+        {{ AST_SUPPORTED_LANGUAGES.join(" / ") }}
+      </n-alert>
+      <n-tabs
+        v-if="supportedLanguages.length"
+        type="segment"
+        v-model:value="activeTab"
+      >
         <n-tab-pane
-          v-for="lang in languages"
+          v-for="lang in supportedLanguages"
           :key="lang"
           :name="lang"
           :tab="lang"
@@ -264,7 +284,7 @@ watch(
                 />
                 <n-select
                   v-if="needsTargetDropdown(rule.engine)"
-                  :options="NODE_TARGET_OPTIONS"
+                  :options="nodeTargetOptions(lang)"
                   :value="rule.target"
                   @update:value="
                     (v: string) => updateRule(lang, index, 'target', v)
@@ -285,7 +305,7 @@ watch(
                 />
                 <n-select
                   v-if="needsOperatorDropdown(rule.engine)"
-                  :options="OPERATOR_TARGET_OPTIONS"
+                  :options="operatorTargetOptions(lang)"
                   :value="rule.target"
                   @update:value="
                     (v: string) => updateRule(lang, index, 'target', v)
@@ -370,7 +390,14 @@ watch(
           </n-flex>
         </n-tab-pane>
       </n-tabs>
-      <n-empty v-else description="请先选择编程语言" />
+      <n-empty
+        v-else
+        :description="
+          languages.length
+            ? '当前语言不支持代码规则检查'
+            : '请先选择编程语言'
+        "
+      />
     </n-collapse-item>
   </n-collapse>
 </template>
diff --git a/apps/web/src/oj/problem/components/SubmissionResult.vue b/apps/web/src/oj/problem/components/SubmissionResult.vue
index 4429968..f74c063 100644
--- a/apps/web/src/oj/problem/components/SubmissionResult.vue
+++ b/apps/web/src/oj/problem/components/SubmissionResult.vue
@@ -178,6 +178,13 @@ const columns: DataTableColumn<Submission["info"]["data"][number]>[] = [
               <Icon :icon="rule.passed ? 'ph:check-bold' : 'ph:x-bold'" />
             </n-icon>
             <span>{{ rule.description }}</span>
+            <!-- 次数类规则光说「出现 2 次 ✗」，学生不知道自己写了几次 -->
+            <span
+              v-if="!rule.passed && rule.actual !== undefined"
+              :style="{ color: theme.errorColor }"
+            >
+              当前 {{ rule.actual }} 次
+            </span>
           </n-flex>
         </n-flex>
       </n-card>
diff --git a/apps/web/src/utils/types.ts b/apps/web/src/utils/types.ts
index d67b9f1..07810f2 100644
--- a/apps/web/src/utils/types.ts
+++ b/apps/web/src/utils/types.ts
@@ -289,7 +289,12 @@ export interface StatisticInfo {
   err_info?: string
   time_cost?: number
   memory_cost?: number
-  ast_results?: Array<{ description: string; passed: boolean }>
+  ast_results?: Array<{
+    description: string
+    passed: boolean
+    /** count_* 规则实际数到的次数，判题机只在这两个引擎上写 */
+    actual?: number
+  }>
 }
 
 /**
diff --git a/bun.lock b/bun.lock
index 6e8b74a..fcde3ef 100644
--- a/bun.lock
+++ b/bun.lock
@@ -24,6 +24,7 @@
         "postgres": "^3.4.9",
         "sql.js": "^1.14.2",
         "tree-sitter-c": "^0.24.1",
+        "tree-sitter-cpp": "^0.23.4",
         "tree-sitter-python": "^0.25.0",
         "web-tree-sitter": "^0.26.13",
         "zod": "^4.4.3",
@@ -1365,6 +1366,8 @@
 
     "tree-sitter-c": ["tree-sitter-c@0.24.1", "https://registry.npmjs.com/tree-sitter-c/-/tree-sitter-c-0.24.1.tgz", { "dependencies": { "node-addon-api": "^8.3.1", "node-gyp-build": "^4.8.4" }, "peerDependencies": { "tree-sitter": "^0.22.4" }, "optionalPeers": ["tree-sitter"] }, "sha512-lkYwWN3SRecpvaeqmFKkuPNR3ZbtnvHU+4XAEEkJdrp3JfSp2pBrhXOtvfsENUneye76g889Y0ddF2DM0gEDpA=="],
 
+    "tree-sitter-cpp": ["tree-sitter-cpp@0.23.4", "", { "dependencies": { "node-addon-api": "^8.2.1", "node-gyp-build": "^4.8.2", "tree-sitter-c": "^0.23.1" }, "peerDependencies": { "tree-sitter": "^0.21.1" }, "optionalPeers": ["tree-sitter"] }, "sha512-qR5qUDyhZ5jJ6V8/umiBxokRbe89bCGmcq/dk94wI4kN86qfdV8k0GHIUEKaqWgcu42wKal5E97LKpLeVW8sKw=="],
+
     "tree-sitter-python": ["tree-sitter-python@0.25.0", "https://registry.npmjs.com/tree-sitter-python/-/tree-sitter-python-0.25.0.tgz", { "dependencies": { "node-addon-api": "^8.5.0", "node-gyp-build": "^4.8.4" }, "peerDependencies": { "tree-sitter": "^0.25.0" }, "optionalPeers": ["tree-sitter"] }, "sha512-eCmJx6zQa35GxaCtQD+wXHOhYqBxEL+bp71W/s3fcDMu06MrtzkVXR437dRrCrbrDbyLuUDJpAgycs7ncngLXw=="],
 
     "treemate": ["treemate@0.3.11", "https://registry.npmjs.com/treemate/-/treemate-0.3.11.tgz", {}, "sha512-M8RGFoKtZ8dF+iwJfAJTOH/SM4KluKOKRJpjCMhI8bG3qB74zrFoArKZ62ll0Fr3mqkMJiQOmWYkdYgDeITYQg=="],
@@ -1537,6 +1540,8 @@
 
     "strip-literal/js-tokens": ["js-tokens@10.0.0", "https://registry.npmjs.com/js-tokens/-/js-tokens-10.0.0.tgz", {}, "sha512-lM/UBzQmfJRo9ABXbPWemivdCW8V2G8FHaHdypQaIy523snUjog0W71ayWXTjiR+ixeMyVHN2XcpnTd/liPg/Q=="],
 
+    "tree-sitter-cpp/tree-sitter-c": ["tree-sitter-c@0.23.6", "", { "dependencies": { "node-addon-api": "^8.3.0", "node-gyp-build": "^4.8.4" }, "peerDependencies": { "tree-sitter": "^0.22.1" }, "optionalPeers": ["tree-sitter"] }, "sha512-0dxXKznVyUA0s6PjNolJNs2yF87O5aL538A/eR6njA5oqX3C3vH4vnx3QdOKwuUdpKEcFdHuiDpRKLLCA/tjvQ=="],
+
     "tsx/esbuild": ["esbuild@0.28.1", "https://registry.npmjs.com/esbuild/-/esbuild-0.28.1.tgz", { "optionalDependencies": { "@esbuild/aix-ppc64": "0.28.1", "@esbuild/android-arm": "0.28.1", "@esbuild/android-arm64": "0.28.1", "@esbuild/android-x64": "0.28.1", "@esbuild/darwin-arm64": "0.28.1", "@esbuild/darwin-x64": "0.28.1", "@esbuild/freebsd-arm64": "0.28.1", "@esbuild/freebsd-x64": "0.28.1", "@esbuild/linux-arm": "0.28.1", "@esbuild/linux-arm64": "0.28.1", "@esbuild/linux-ia32": "0.28.1", "@esbuild/linux-loong64": "0.28.1", "@esbuild/linux-mips64el": "0.28.1", "@esbuild/linux-ppc64": "0.28.1", "@esbuild/linux-riscv64": "0.28.1", "@esbuild/linux-s390x": "0.28.1", "@esbuild/linux-x64": "0.28.1", "@esbuild/netbsd-arm64": "0.28.1", "@esbuild/netbsd-x64": "0.28.1", "@esbuild/openbsd-arm64": "0.28.1", "@esbuild/openbsd-x64": "0.28.1", "@esbuild/openharmony-arm64": "0.28.1", "@esbuild/sunos-x64": "0.28.1", "@esbuild/win32-arm64": "0.28.1", "@esbuild/win32-ia32": "0.28.1", "@esbuild/win32-x64": "0.28.1" }, "bin": { "esbuild": "bin/esbuild" } }, "sha512-HrJrvZv5ayxBzPfwphOoNzkzOIIlifzk0KJrGK2c8R4+LKpMtpYLQeUdjnwjWv/LZlkH2laZk+4w78pi99D4Vw=="],
 
     "unplugin-vue-components/magic-string": ["magic-string@0.30.21", "https://registry.npmjs.com/magic-string/-/magic-string-0.30.21.tgz", { "dependencies": { "@jridgewell/sourcemap-codec": "^1.5.5" } }, "sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ=="],
diff --git a/packages/contract/src/problem.ts b/packages/contract/src/problem.ts
index 2fa7f7d..57bbb6d 100644
--- a/packages/contract/src/problem.ts
+++ b/packages/contract/src/problem.ts
@@ -99,26 +99,156 @@ export const astRuleSchema = z.object({
 export const astRulesSchema = z.record(z.string(), z.array(astRuleSchema))
 
 /**
- * 节点类型的中文名。后台编辑器的下拉选项、后端生成要求文案都要用它 ——
- * 原来在 AstRulesEditor.vue（下拉 options）和 ProblemContent.vue
- * （NODE_TARGET_LABELS）各存了一份同样的 15 条。
+ * 每种语言支持哪些节点 target，以及它的中文名。原来这里是一张 15 条的混合表，
+ * C 和 Python 的节点混在一起铺成后台下拉（更早之前 AstRulesEditor.vue 和
+ * ProblemContent.vue 还各手抄了一份）。
+ *
+ * **键必须和 judge/ast.ts 的 mappings 逐一对齐** —— 那边是 target → tree-sitter
+ * 节点类型，这边是 target → 中文名。少一边就是静默故障：老师给 C 题选到只有
+ * Python 有的 `list_comprehension`，判题机 `mapping[target] ?? target` 拿裸名去比
+ * 节点类型，C 的语法树里永远不存在它，于是「必须使用列表推导式」永远失败、
+ * 「不能使用 f-string」永远通过，两头都不报错。
  */
-export const AST_NODE_TARGET_LABELS: Record<string, string> = {
-  for_loop: "for 循环",
-  while_loop: "while 循环",
-  if_statement: "if 条件",
-  else_clause: "else 子句",
-  function_definition: "函数定义",
-  return: "return 语句",
-  break: "break 语句",
-  continue: "continue 语句",
-  list_comprehension: "列表推导式",
-  list_literal: "列表",
-  dict_literal: "字典",
-  set_literal: "集合",
-  f_string: "f-string",
-  try_except: "try-except",
-  class_definition: "类定义",
+export const AST_NODE_TARGETS_BY_LANGUAGE: Record<string, Record<string, string>> = {
+  C: {
+    for_loop: "for 循环",
+    while_loop: "while 循环",
+    do_while: "do-while 循环",
+    if_statement: "if 条件",
+    else_clause: "else 子句",
+    switch_statement: "switch 语句",
+    case_statement: "case 分支",
+    break: "break 语句",
+    continue: "continue 语句",
+    return: "return 语句",
+    function_definition: "函数定义",
+    assignment: "赋值语句",
+    struct: "结构体",
+    include: "#include 指令",
+  },
+  // tree-sitter-cpp 继承 tree-sitter-c 的语法，C 那 14 条 target 在 C++ 树里
+  // 逐个实测通用，所以这张表是「C 的全集 + C++ 独有的几条」
+  "C++": {
+    for_loop: "for 循环",
+    range_for_loop: "范围 for 循环",
+    while_loop: "while 循环",
+    do_while: "do-while 循环",
+    if_statement: "if 条件",
+    else_clause: "else 子句",
+    switch_statement: "switch 语句",
+    case_statement: "case 分支",
+    break: "break 语句",
+    continue: "continue 语句",
+    return: "return 语句",
+    function_definition: "函数定义",
+    class_definition: "类定义",
+    struct: "结构体",
+    assignment: "赋值语句",
+    include: "#include 指令",
+    try_except: "try-catch",
+    throw: "throw 语句",
+    namespace: "namespace 定义",
+    template: "模板定义",
+    lambda: "lambda 表达式",
+    using: "using 声明",
+  },
+  Python3: {
+    for_loop: "for 循环",
+    while_loop: "while 循环",
+    if_statement: "if 条件",
+    elif_clause: "elif 子句",
+    else_clause: "else 子句",
+    break: "break 语句",
+    continue: "continue 语句",
+    return: "return 语句",
+    function_definition: "函数定义",
+    class_definition: "类定义",
+    assignment: "赋值语句",
+    try_except: "try-except",
+    with_statement: "with 语句",
+    import: "import 语句",
+    import_from: "from-import 语句",
+    list_comprehension: "列表推导式",
+    list_literal: "列表",
+    dict_literal: "字典",
+    set_literal: "集合",
+    f_string: "f-string",
+  },
+}
+
+/**
+ * 运算符 target → 该语言里的实际写法。逻辑名 `and` / `or` / `not` 在 C 里写作
+ * `&&` / `||` / `!`，判题机按 mappings 翻译，文案这边也得翻 —— 否则 C 题的学生
+ * 看到的要求是「必须使用 and 运算符」，而 C 里根本没有 `and` 这个词。
+ *
+ * 恒等的那些条目（`+`、`==` …）判题机的 mappings 里已经删掉了，走 `?? target`
+ * 回落到同一个值；这里保留完整列表是因为它同时是后台下拉的选项来源。
+ */
+export const AST_OPERATOR_TARGETS_BY_LANGUAGE: Record<string, Record<string, string>> = {
+  C: {
+    "+": "+", "-": "-", "*": "*", "/": "/", "%": "%",
+    "+=": "+=", "-=": "-=", "*=": "*=", "/=": "/=", "%=": "%=",
+    "++": "++", "--": "--",
+    "==": "==", "!=": "!=", ">": ">", ">=": ">=", "<": "<", "<=": "<=",
+    and: "&&", or: "||", not: "!",
+    "&": "&", "|": "|",
+  },
+  // `<<` / `>>` 对 C++ 主要是 cout/cin 的流运算符（位移是同一个 token）
+  "C++": {
+    "+": "+", "-": "-", "*": "*", "/": "/", "%": "%",
+    "+=": "+=", "-=": "-=", "*=": "*=", "/=": "/=", "%=": "%=",
+    "++": "++", "--": "--",
+    "==": "==", "!=": "!=", ">": ">", ">=": ">=", "<": "<", "<=": "<=",
+    and: "&&", or: "||", not: "!",
+    "&": "&", "|": "|", "<<": "<<", ">>": ">>",
+  },
+  Python3: {
+    "+": "+", "-": "-", "*": "*", "/": "/", "//": "//", "%": "%", "**": "**",
+    "+=": "+=", "-=": "-=", "*=": "*=", "/=": "/=", "%=": "%=",
+    "==": "==", "!=": "!=", ">": ">", ">=": ">=", "<": "<", "<=": "<=",
+    and: "and", or: "or", not: "not",
+    "&": "&", "|": "|",
+  },
+}
+
+/**
+ * 判题机真正能做 AST 检查的语言。设计文档写的是"支持全部 6 种语言"，落地的只有
+ * 这两种 —— 其余语言 judge/ast.ts 的 loadLanguage 返回 null，规则一条都不会跑。
+ * 所以后台不给别的语言开 tab，题目页也不把它们的规则展示成「要求」。
+ */
+export const AST_SUPPORTED_LANGUAGES = Object.keys(AST_NODE_TARGETS_BY_LANGUAGE)
+
+/** 全语言的节点中文名并集，只给拿不到语言的场合做回落。有语言一律走 astNodeLabel() */
+export const AST_NODE_TARGET_LABELS: Record<string, string> = Object.assign(
+  {},
+  ...Object.values(AST_NODE_TARGETS_BY_LANGUAGE),
+)
+
+export function astNodeLabel(target: string, language?: string): string {
+  const table = language ? AST_NODE_TARGETS_BY_LANGUAGE[language] : undefined
+  return table?.[target] ?? AST_NODE_TARGET_LABELS[target] ?? target
+}
+
+export function astOperatorLabel(target: string, language?: string): string {
+  return (language ? AST_OPERATOR_TARGETS_BY_LANGUAGE[language]?.[target] : undefined) ?? target
+}
+
+/**
+ * count_* 引擎至少要有一个数字约束，否则这条规则恒真 —— rangePassed 三个字段全
+ * undefined 直接返回 true，描述也退化成光秃秃一个「for 循环」。编辑器切到
+ * 「出现次数」时会清掉 exact/min/max，老师不填数字就会存出这种规则。
+ *
+ * 读取路径（判题、题目页要求）用它把这种规则整条丢掉，而不是让 schema 校验失败：
+ * astRulesSchema 同时用于**读**后台题目详情，在那儿抛错会让整个详情打不开。
+ */
+export function astRuleIsMeaningful(rule: {
+  engine: string
+  exact?: number
+  min?: number
+  max?: number
+}): boolean {
+  if (!rule.engine.startsWith("count")) return true
+  return rule.exact !== undefined || rule.min !== undefined || rule.max !== undefined
 }
 
 /**