자료 공유

function solution(genres, plays) {
    const table = new Map();
    const arr = [];
    for (let i = 0; i < genres.length; i++) {
        arr.push([genres[i], plays[i]]);
    }
    for (let i = 0; i < arr.length; i++) {
        const data = table.get(arr[i][0]) || { total: 0, songs: []}
        table.set(arr[i][0], {
            total: data.total + arr[i][1],
            songs: [...data.songs, [arr[i][1], i]]
                .sort((a, b) => b[0] - a[0])
                .slice(0, 2)
        })
    }
    return [...table.entries()]
        .sort((a, b) => b[1].total - a[1].total)
        .flatMap(item => item[1].songs)
        .map(song => song[1])
}