import pandas as pd

nowcoder = pd.read_csv("nowcoder.csv")
nowcoder["date"] = pd.to_datetime(nowcoder["date"], format="%Y/%m/%d %H:%M")
nowcoder["date"] = nowcoder["date"][(nowcoder["date"].dt.year == 2021) & (nowcoder["date"].dt.month == 12)]
nowcoder["rank"] = pd.to_timedelta(nowcoder.groupby("user_id")["date"].rank(), unit="D")
nowcoder["same_date"] = (nowcoder["date"] - nowcoder["rank"]).dt.strftime("%Y-%m-%d")
data = (nowcoder.groupby(["user_id", "same_date"])["rank"].count().groupby("user_id").max())
print(data[data >= 3])