统计每用户平均卡片数与分布

def solve():
    from pyodide.http import open_url
    from io import StringIO
    import pandas as pd
    cards=pd.read_csv(StringIO(open_url("https://data.zuihe.com/dbd/ms-memcard/state_00/cards.csv").read()))
    users=pd.read_csv(StringIO(open_url("https://data.zuihe.com/dbd/ms-memcard/state_00/users.csv").read()))
    by_user=cards.groupby('user_id').size().reset_index(name='card_count')
    merged=by_user.merge(users[['user_id','name']],on='user_id',how='left')
    print(f"Cards per user: avg={round(by_user['card_count'].mean(),1)} max={by_user['card_count'].max()} min={by_user['card_count'].min()}")
    for _,r in merged.sort_values('card_count',ascending=False).head(8).iterrows():
        print(f"  {r['name']}: {r['card_count']} cards")