假设我有一组用户、一组歌曲和每首歌曲的一组投票:
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User Song Vote
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user1 song1 [score]
user1 song2 [score]
user1 song3 [score]
user2 song1 [score]
user2 song2 [score]
user2 song3 [score]
user3 song1 [score]
user3 song2 [score]
user3 song3 [score]
user-n song-n [score]
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根据歌曲投票计算用户相似度的最有效方法是什么?有没有比遍历每个用户和对每首歌的每次投票更好的方法?