[프로그래머스] 고득점 키트 - 해시2

오늘 푼 문제

 

2. 베스트앨범 / Lv.3 / 시간 : 36분

programmers.co.kr/learn/courses/30/lessons/42579?language=javascript

코딩테스트 연습 - 베스트앨범

function solution(genres, plays) {
    
    const hash = genres.reduce((acc,genre,index)=>{
        acc[genre] = acc[genre] || {total : 0, maxIndex : null, secondIndex : null};
        acc[genre].total += plays[index];
        
        if(plays[index] > (plays[acc[genre].maxIndex] || 0)){
            acc[genre].secondIndex = acc[genre].maxIndex;
            acc[genre].maxIndex = index;
        }else if(plays[index] > (plays[acc[genre].secondIndex]||0)){
            acc[genre].secondIndex = index;
        } 
        
        return acc;
    },{});
    
    const sorted = Object.values(hash).sort((a,b)=>b.total-a.total);
    
    const answer = sorted.reduce((acc,cur)=>{
        acc.push(cur.maxIndex);
        if(cur.secondIndex!==null) acc.push(cur.secondIndex);
        return acc;
    },[]);
    
    return answer;
}