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function solution(genres, plays) {
    const album = {};

    genres
    .forEach((key, index) => {
        album[key] = [...(album[key] ?? []), [index, plays[index]]];
    });

    return Object.keys(album)
    .map(key => [key, album[key].reduce((acc, array) => acc + array[1], 0), album[key]])
    .sort((a, b) => b[1] - a[1])
    .filter((_, index) => index < 2)
    .map(array => array[2])
    .map(album => album.sort((a, b) => b[1] - a[1]))
    .map(album => album.filter((_, index) => index < 2))
    .map(albums => albums.map(album => album[0]))
    .flat();

}