베스트앨범

문제 출처 : https://programmers.co.kr/learn/courses/30/lessons/42579

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코딩테스트 연습 - 베스트앨범

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1차 실패

from collections import Counter
def solution(genres, plays):
    m=[]
    answer=[]
    d={}
    for i,name in enumerate(genres):
        answer.append([i,name,plays[i]])
    answer.sort(reverse=True, key=lambda x:x[2])
    answer.sort(reverse=True, key=lambda x:x[1])
    for i in range(len(genres)):
        if genres[i] in d:
            d[genres[i]]+=plays[i]
        else:
            d[genres[i]]=plays[i]
    di=sorted(d.items(),reverse=True, key=lambda x:x[1])
    for i in range(len(answer)):
        for j in range(len(di)):
            if di[j][0] in answer[i]:
                m.append(answer[i][0])
                if len(m)==2*(j+1):
                    break
    return m

2차 실패

def solution(genres, plays):
    m=[]
    answer=[]
    d={}
    for i,name in enumerate(genres):
        answer.append([i,name,plays[i]])
    answer.sort(reverse=True, key=lambda x:x[2])
    answer.sort(reverse=True, key=lambda x:x[1])
    for i in range(len(genres)):
        if genres[i] in d:
            d[genres[i]]+=plays[i]
        else:
            d[genres[i]]=plays[i]
    di=sorted(d.items(),reverse=True, key=lambda x:x[1])
    for i in range(len(di)):
        for j in range(len(answer)):
            if j>2:
                break
            elif di[i][0] in answer[j]:
                m.append(answer[j][0])
        answer.pop(0)
    return m

3차 실패

from collections import Counter
def solution(genres, plays):
    m=[]
    answer=[]
    d={}
    for i,name in enumerate(genres):
        answer.append([i,name,plays[i]])
    answer.sort(reverse=True, key=lambda x:x[2])
    answer.sort(reverse=True, key=lambda x:x[1])
    for i in range(len(genres)):
        if genres[i] in d:
            d[genres[i]]+=plays[i]
        else:
            d[genres[i]]=plays[i]
    di=sorted(d.items(),reverse=True, key=lambda x:x[1])
    for i in range(len(di)):
        j=0
        for _ in range(2):
            if di[i][0] in answer[j]:
                m.append(answer[j][0])
                del answer[j]
    return m

4차 성공

from operator import itemgetter
def solution(genres, plays):
    d={}
    answer=[]
    for i in range(len(genres)):
        if genres[i] not in d:
            d[genres[i]]=[]
            d[genres[i]].append(0)
        d[genres[i]].append((i,plays[i]))
        d[genres[i]][0]+=plays[i]
    a=list(d.values())
    a.sort(reverse=True, key=itemgetter(0))
    while a:
        a[0].pop(0)
        a[0].sort(reverse=True, key=itemgetter(1))
        for i in range(len(a[0])):
            if i>=2:
                break
            answer.append(a[0][i][0])
        a.pop(0)
    return answer

처음에 너무 복잡하게 list를 많이 만들고 2개 이상의 곡을 가지고 있는 장르를 감당하지 못해 에러가 난 것 같다..

다른 분의 풀이를 보고 도움을 받았는데 이렇게 간단하게 풀수있다니,,,,,,,,,,

그래도 덕분에 itemgetter 사용법도 알게 되었다..!

갠적으루 lambda보다 itemgetter가 훨씬 편해,,,,

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itemgetter 사용하기