✨ Add arc to contest type (#747)

Author: KATO-Hiro

src/lib/utils/contest.ts

@@ -8,6 +8,10 @@ export const classifyContest = (contest_id: string) => {
     return ContestType.ABC;
   }
 
+  if (/^arc\d{3}$/.exec(contest_id)) {
+    return ContestType.ARC;
+  }
+
   if (contest_id.startsWith('APG4b')) {
     return ContestType.APG4B;
   }
@@ -57,7 +61,9 @@ export const classifyContest = (contest_id: string) => {
   return null;
 };
 
-// priority: 0 (High) - 11 (Low)
+// priority: 0 (High) - 12 (Low)
+// HACK: ARCの優先順位は暫定版
+//
 // See:
 // https://jsprimer.net/basic/map-and-set/
 export const contestTypePriorities: Map<ContestType, number> = new Map([
@@ -72,7 +78,8 @@ export const contestTypePriorities: Map<ContestType, number> = new Map([
   [ContestType.JOI, 8],
   [ContestType.TESSOKU_BOOK, 9],
   [ContestType.MATH_AND_ALGORITHM, 10],
-  [ContestType.OTHERS, 11],
+  [ContestType.ARC, 11],
+  [ContestType.OTHERS, 12],
 ]);
 
 export function getContestPriority(contestId: string): number {