add multicast works problem json file

data/3.网络高阶/4.组播/2.组播的工作原理/1.json

+{
+  "type": "code_options",
+  "author": "JoshuaYu",
+  "source": "1.md",
+  "notebook_enable": false,
+  "exercise_id": "eeb96f504e064f9ab5bec73207dd3c4c"
+}
\ No newline at end of file

data/3.网络高阶/4.组播/2.组播的工作原理/2.json

+{
+  "type": "code_options",
+  "author": "JoshuaYu",
+  "source": "2.md",
+  "notebook_enable": false,
+  "exercise_id": "6137cca2fe234f4ca0764eebd2eff0a2"
+}
\ No newline at end of file

data/3.网络高阶/4.组播/2.组播的工作原理/3.json

+{
+  "type": "code_options",
+  "author": "JoshuaYu",
+  "source": "3.md",
+  "notebook_enable": false,
+  "exercise_id": "7a0615b36ccc463589d1221793c6f796"
+}
\ No newline at end of file

data/3.网络高阶/4.组播/2.组播的工作原理/config.json

 {
   "node_id": "network-0d31ea1646204361b903ff004a3a86c4",
-  "keywords": ["组播工作原理"],
+  "keywords": [
+    "组播工作原理"
+  ],
   "children": [],
-  "export": [],
+  "export": [
+    "1.json",
+    "2.json",
+    "3.json"
+  ],
   "keywords_must": [],
   "keywords_forbid": []
 }
\ No newline at end of file