fix.

src/oj/problem/components/Editor.vue

@@ -13,7 +13,8 @@ const route = useRoute()
 const contestID = !!route.params.contestID ? route.params.contestID : null
 
 const storageKey = computed(
-  () => `problem_${problem.value!._id}_contest_${contestID}`
+  () =>
+    `problem_${problem.value!._id}_contest_${contestID}_lang_${code.language}`
 )
 
 onMounted(() => {
@@ -29,18 +30,26 @@ const editorHeight = computed(() =>
   isDesktop.value ? "calc(100vh - 133px)" : "calc(100vh - 172px)"
 )
 
-function reset() {
-  storage.remove(storageKey.value)
-}
-
 function changeCode(v: string) {
   storage.set(storageKey.value, v)
 }
+
+function changeLanguage(v: string) {
+  if (
+    storage.get(storageKey.value) &&
+    storageKey.value.split("_").pop() === v
+  ) {
+    code.value = storage.get(storageKey.value)
+  } else {
+    code.value =
+      problem.value!.template[code.language] || SOURCES[code.language]
+  }
+}
 </script>
 
 <template>
   <n-space vertical>
-    <Form @reset="reset" />
+    <Form @change-language="changeLanguage" />
     <CodeEditor
       v-model="code.value"
       @update:model-value="changeCode"

src/oj/problem/components/Form.vue

@@ -13,13 +13,10 @@ const route = useRoute()
 const router = useRouter()
 const userStore = useUserStore()
 
-const emit = defineEmits(["reset"])
-
-watch(() => code.language, reset)
+const emit = defineEmits(["changeLanguage"])
 
 function reset() {
   code.value = problem.value!.template[code.language] || SOURCES[code.language]
-  emit("reset")
 }
 
 function goSubmissions() {
@@ -71,6 +68,7 @@ function select(key: string) {
 
 function changeLanguage(v: LANGUAGE) {
   storage.set(STORAGE_KEY.LANGUAGE, v)
+  emit("changeLanguage", v)
 }
 </script>