How hard is LeetCode 1731. The Number of Employees Which Report to Each Employee?

LeetCode 1731. The Number of Employees Which Report to Each Employee is rated Easy on LeetCode.

What topics does LeetCode 1731. The Number of Employees Which Report to Each Employee cover?

LeetCode 1731. The Number of Employees Which Report to Each Employee is tagged Database on LeetCode.

The Number of Employees Which Report to Each Employee — LeetCode 1731 Python Solution

EasyDatabase

Problem: #1731
Reading time: 3 min
Source: leetcode.com

Table schema

SQL

Table: Employees +-------------+----------+ | Column Name | Type | +-------------+----------+ | employee_id | int | | name | varchar | | reports_to | int | | age | int | +-------------+----------+ employee_id is the column with unique values for this table. This table contains information about the employees and the id of the manager they report to.

Example

SQL

+-------------+----------+
| Column Name | Type     |
+-------------+----------+
| employee_id | int      |
| name        | varchar  |
| reports_to  | int      |
| age         | int      |
+-------------+----------+
employee_id is the column with unique values for this table.
This table contains information about the employees and the id of the manager they report to. Some employees do not report to anyone (reports_to is null).

Python solution

Python

import duckdb
import pandas as pd

def solution(employees: pd.DataFrame) -> pd.DataFrame:
    con = duckdb.connect()
    con.register("Employees", employees)
    return con.execute("""SELECT
    e2.employee_id,
    e2.name,
    COUNT(1) AS reports_count,
    ROUND(AVG(e1.age)) AS average_age
FROM
    Employees AS e1
    JOIN Employees AS e2 ON e1.reports_to = e2.employee_id
GROUP BY 1
ORDER BY 1;""").df()

Complexity

Measure	Complexity
Time	O(n log n) (typical)
Space	O(n) auxiliary

Frequently asked questions

How hard is LeetCode 1731. The Number of Employees Which Report to Each Employee?: LeetCode 1731. The Number of Employees Which Report to Each Employee is rated Easy on LeetCode.
What topics does LeetCode 1731. The Number of Employees Which Report to Each Employee cover?: LeetCode 1731. The Number of Employees Which Report to Each Employee is tagged Database on LeetCode.