Find Customer Referee — LeetCode 584 Python Solution

The problem

List the names of the customers who were not referred by the customer with id 2, which includes everyone who was not referred by anybody. The Customer table has id (int, primary key), name (varchar) and referee_id (int), the id of the customer who referred them, or null when nobody did. Return the names in a column called name.

Example

Input

Customer(id, name, referee_id) = (1, 'Ana', null), (2, 'Ben', null), (3, 'Cleo', 2), (4, 'Dev', 1), (5, 'Eve', 2)

Output

name = 'Ana', 'Ben', 'Dev'

Explanation

Only Cleo and Eve carry referee_id 2; the rows with a null referee_id are kept because "not referred by 2" includes "not referred at all".

Python solution

import pandas as pd

def find_customer_referee(customer: pd.DataFrame) -> pd.DataFrame:
    res = customer[(customer['referee_id'].isna()) | (customer['referee_id'] != 2)]
    return res[['name']]

Complexity

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