core&ui: fix contest with more than 26 problems have wrong alphabetic id (#1008)

Co-authored-by: undefined <i@undefined.moe>

packages/hydrooj/src/handler/contest.ts

@@ -5,7 +5,7 @@ import { escapeRegExp, pick } from 'lodash';
 import moment from 'moment-timezone';
 import { ObjectId } from 'mongodb';
 import {
-    Counter, diffArray, randomstring, sortFiles, Time, yaml,
+    Counter, diffArray, getAlphabeticId, randomstring, sortFiles, Time, yaml,
 } from '@hydrooj/utils/lib/utils';
 import { Context, Service } from '../context';
 import {
@@ -132,7 +132,7 @@ export class ContestDetailBaseHandler extends Handler {
             },
             {
                 name: 'problem_detail',
-                displayName: `${String.fromCharCode(65 + this.tdoc.pids.indexOf(pdoc.docId))}. ${pdoc.title}`,
+                displayName: `${getAlphabeticId(this.tdoc.pids.indexOf(pdoc.docId))}. ${pdoc.title}`,
                 args: { query: { tid }, pid: pdoc.docId, prefix: 'contest_detail_problem' },
                 checker: () => 'pdoc' in this,
             },
@@ -791,7 +791,7 @@ export async function apply(ctx: Context) {
                 const teamIds: Record<number, number> = {};
                 for (let i = 1; i <= teams.length; i++) teamIds[teams[i - 1].uid] = i;
                 const time = (t: ObjectId) => Math.floor((t.getTimestamp().getTime() - tdoc.beginAt.getTime()) / Time.second);
-                const pid = (i: number) => String.fromCharCode(65 + i);
+                const pid = (i: number) => getAlphabeticId(i);
                 const escape = (i: string) => i.replace(/[",]/g, '');
                 const unknownSchool = this.translate('Unknown School');
                 const statusMap = {