competition from https://tianchi.shuju.aliyun.com/getStart/introduction.htm?spm=5176.100067.5678.1.rqpAsr&raceId=231574
model 1: use user's history weibos mean as prediction. test performance was 26.48741449%
model 2: use the weibo keywords vectors distance to find the closest weibo in user's history weibos. test performance was ??