Class Reservations and Waitlist Counts

PandasMediumMid level~10 min

Problem

You are given two DataFrames. `classes` (from `classes.csv`) has columns `class_id` (the primary key) and `max_spots` (how many members the studio room physically holds). `signups` (from `signups.csv`) has columns `member_id` and `class_id`; each row is one member signing up for one class. Sign-ups beyond `max_spots` go onto a waitlist.

For every class, report `class_id`, `reserved_cnt` (members who got a confirmed spot, capped at `max_spots`), and `waitlist_cnt` (members who overflowed onto the waitlist, or 0 if none). Include classes with no sign-ups. Order by `class_id`.

Input data

Example rows — the live problem includes the full dataset.

classes

class_id	max_spots
1	2
2	5
3	1

signups

member_id	class_id
10	1
11	1
12	1
13	2
14	2

Expected output

Your answer should return 3 rows with the columns class_id, reserved_cnt, waitlist_cnt.

Starter code (Pandas (Python))

import pandas as pd

def class_reservations_and_waitlist(classes, signups) -> pd.DataFrame:
    # Your code here
    return classes

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