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export default function isAnagram(s: string, t: string): boolean {    if (s.length !== t.length) {        return false;    }
    const map: Record<string, number | undefined> = {};    for (const c of s) {        map[c] = 1 + (map[c] ?? 0);    }    for (const c of t) {        const count = -1 + (map[c] ?? 0);        map[c] = count;        if (count < 0) return false;    }    return Object.values(map).every((a) => a === 0);}