The Most Frequently Ordered Products for Each Customer — LeetCode 1596 Python Solution

MediumLeetCode PremiumDatabase
Problem
#1596
Reading time
5 min

Table schema

SQL
Table: Customers +---------------+---------+ | Column Name | Type | +---------------+---------+ | customer_id | int | | name | varchar | +---------------+---------+ customer_id is the column with unique values for this table. This table contains information about the customers.

Example

SQL
+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| customer_id   | int     |
| name          | varchar |
+---------------+---------+
customer_id is the column with unique values for this table.
This table contains information about the customers.

Python solution

Python
import duckdb
import pandas as pd

def solution(customers: pd.DataFrame, orders: pd.DataFrame, products: pd.DataFrame) -> pd.DataFrame:
    con = duckdb.connect()
    con.register("Customers", customers)
    con.register("Orders", orders)
    con.register("Products", products)
    return con.execute("""WITH
    T AS (
        SELECT
            customer_id,
            product_id,
            RANK() OVER (
                PARTITION BY customer_id
                ORDER BY COUNT(1) DESC
            ) AS rk
        FROM Orders
        GROUP BY 1, 2
    )
SELECT customer_id, product_id, product_name
FROM
    T
    JOIN Products USING (product_id)
WHERE rk = 1;""").df()

Complexity

MeasureComplexity
TimeO(n log n) (typical)
SpaceO(n) auxiliary

Related problems

Frequently asked questions

How hard is LeetCode 1596. The Most Frequently Ordered Products for Each Customer?
LeetCode 1596. The Most Frequently Ordered Products for Each Customer is rated Medium on LeetCode.
What topics does LeetCode 1596. The Most Frequently Ordered Products for Each Customer cover?
LeetCode 1596. The Most Frequently Ordered Products for Each Customer is tagged Database on LeetCode.
Is LeetCode 1596. The Most Frequently Ordered Products for Each Customer a premium problem?
Yes. LeetCode 1596. The Most Frequently Ordered Products for Each Customer is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.

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