[프로그래머스 Lv.3] 해시 - 베스트앨범

✨ 문제 ✨

✨ 정답 ✨

function solution(genres, plays) {

    const genreTotalPlays = {};

    const genreSongs = {};
    
    for (let i = 0; i < genres.length; i++) {
        const genre = genres[i];
        const play = plays[i];
        
        if (!genreTotalPlays[genre]) {
            genreTotalPlays[genre] = 0;
            genreSongs[genre] = [];
        }
        
        genreTotalPlays[genre] += play;
        genreSongs[genre].push({ index: i, play: play });
    }
    

    const sortedGenres = Object.keys(genreTotalPlays).sort((a, b) => {
        return genreTotalPlays[b] - genreTotalPlays[a];
    });
    
    const answer = [];

    sortedGenres.forEach(genre => {
        const songs = genreSongs[genre];
        songs.sort((a, b) => {
            if (a.play === b.play) {
                return a.index - b.index;
            } else {
                return b.play - a.play;
            }
        });
        
        answer.push(songs[0].index);
        if (songs.length > 1) {
            answer.push(songs[1].index);
        }
    });
    
    return answer;
}

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