Gender Cycle Display Order

Medium

A profile feed service needs a deterministic presentation order for a batch of user records. The data team stores user IDs and a gender bucket, then asks the query layer to emit rows in a strict repeating sequence. Table: Genders user_id: unique user identifier gender: one of 'female', 'other', or 'male' Data guarantee: The input has the same number of rows for each gender category. Task: Reorder rows so the final output cycles in this exact pattern: female, then other, then male, and repeat. Ordering rule inside each category: For female rows, sort user_id ascending before interleaving. For other rows, sort user_id ascending before interleaving. For male rows, sort user_id ascending before interleaving. Output requirements: Return exactly these columns in this order: user_id, gender The row order must follow the cycle exactly. Supported submission environments: SQL (SQLite 3.27.2) Pandas (Python)

Example 1

Input

Genders:
| user_id | gender |
|---------|--------|
| 4       | male   |
| 7       | female |
| 2       | other  |
| 5       | male   |
| 3       | female |
| 8       | male   |
| 6       | other  |
| 1       | other  |
| 9       | female |

Output

[
  {"user_id":3,"gender":"female"},
  {"user_id":1,"gender":"other"},
  {"user_id":4,"gender":"male"},
  {"user_id":7,"gender":"female"},
  {"user_id":2,"gender":"other"},
  {"user_id":5,"gender":"male"},
  {"user_id":9,"gender":"female"},
  {"user_id":6,"gender":"other"},
  {"user_id":8,"gender":"male"}
]

Explanation

Each gender group is sorted by user_id first: female=[3,7,9], other=[1,2,6], male=[4,5,8]. Then rows are interleaved as female, other, male at each index.

Example 2

Input

Genders:
| user_id | gender |
|---------|--------|
| 40      | female |
| 11      | male   |
| 30      | other  |
| 5       | female |
| 99      | male   |
| 20      | other  |

Output

[
  {"user_id":5,"gender":"female"},
  {"user_id":20,"gender":"other"},
  {"user_id":11,"gender":"male"},
  {"user_id":40,"gender":"female"},
  {"user_id":30,"gender":"other"},
  {"user_id":99,"gender":"male"}
]

Explanation

Even when input rows are mixed, each bucket is independently sorted, then interleaved by cycle order.

Example 3

Input

Genders:
[]

Output

[]

Explanation

An empty input produces an empty output.

Constraints

0 <= number of rows in Genders <= 1800
1 <= user_id <= 2000000000
gender is one of: female, other, male
user_id values are unique
Counts of female, other, and male rows are equal
Return exactly two columns: user_id, gender
Output order must repeat female -> other -> male
Within each gender, user_id order is ascending
For SQL submissions, use SQLite 3.27.2 semantics
For Pandas submissions, return a DataFrame with columns: user_id, gender

Genders: | user_id | gender | |---------|--------| | 4 | male | | 7 | female | | 2 | other | | 5 | male | | 3 | female | | 8 | male | | 6 | other | | 1 | other | | 9 | female |

[ {"user_id":3,"gender":"female"}, {"user_id":1,"gender":"other"}, {"user_id":4,"gender":"male"}, {"user_id":7,"gender":"female"}, {"user_id":2,"gender":"other"}, {"user_id":5,"gender":"male"}, {"user_id":9,"gender":"female"}, {"user_id":6,"gender":"other"}, {"user_id":8,"gender":"male"} ]

[ {"user_id":5,"gender":"female"}, {"user_id":20,"gender":"other"}, {"user_id":11,"gender":"male"}, {"user_id":40,"gender":"female"}, {"user_id":30,"gender":"other"}, {"user_id":99,"gender":"male"} ]