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export default function maxVowels(s: string, k: number): number {    let res = 0;    const n = s.length;    let v = 0;    for (let i = 0; i < n; i++) {        v += Number(yuanyin.has(s[i]));        if (i === k - 1) {            res = v;        }
        if (i >= k) {            v -= Number(yuanyin.has(s[i - k]));            res = Math.max(res, v);        }    }
    return Math.min(k, res);}const yuanyin = new Set(["a", "e", "i", "o", "u"]);