Is Order Two Columns Independently easy or hard?

Order Two Columns Independently is categorized as Medium difficulty. The challenge is recognizing that both columns must be sorted separately and then aligned using generated row numbers, which requires familiarity with SQL window functions.

Order Two Columns Independently Python/Java solution

This problem is designed for SQL rather than general-purpose languages like Python or Java. The typical solution uses MySQL queries with ROW_NUMBER() and ORDER BY to independently sort columns and recombine them through a join.

How to solve Order Two Columns Independently in O(n)?

Achieving true O(n) time is not practical because the problem requires sorting values in two columns. Sorting-based solutions inherently take O(n log n). The optimal SQL approach sorts each column separately and aligns rows using ROW_NUMBER().

What is the best approach for Order Two Columns Independently?

The best approach uses SQL window functions with ROW_NUMBER(). Sort the first column in ascending order and the second column in descending order, assign row numbers to both sorted results, then join them by the generated index. This method is concise, readable, and works efficiently in modern MySQL and other SQL databases.

Is Order Two Columns Independently asked at Google/Amazon/Meta?

Database ordering and window function problems commonly appear in SQL interview rounds at companies like Amazon, Meta, and data-focused roles at Google. This problem specifically tests understanding of sorting, row numbering, and query composition using window functions.

What data structure is used in Order Two Columns Independently?

The problem primarily relies on SQL window functions rather than traditional data structures. ROW_NUMBER() generates sequential indices after sorting, which act as temporary keys used to join the two independently ordered result sets.

What is the time complexity of Order Two Columns Independently?

The dominant operation is sorting each column independently. Sorting takes O(n log n) time, and the final join by row number runs in O(n). Overall complexity is O(n log n) time with O(n) auxiliary space for intermediate query results.

2159. Order Two Columns Independently - Practice Online

Table: Data

+-------------+------+
| Column Name | Type |
+-------------+------+
| first_col   | int  |
| second_col  | int  |
+-------------+------+
This table may contain duplicate rows.

Write a solution to independently:

order first_col in ascending order.
order second_col in descending order.

The result format is in the following example.

Example 1:

Input: 
Data table:
+-----------+------------+
| first_col | second_col |
+-----------+------------+
| 4         | 2          |
| 2         | 3          |
| 3         | 1          |
| 1         | 4          |
+-----------+------------+
Output: 
+-----------+------------+
| first_col | second_col |
+-----------+------------+
| 1         | 4          |
| 2         | 3          |
| 3         | 2          |
| 4         | 1          |
+-----------+------------+