Double Round-Robin League Fixtures

Easy

A sports operations platform stores the participating clubs of a league season in a Teams table. The scheduling service needs a complete list of directed fixtures for a double round-robin stage, where each pair of clubs plays twice with swapped home and away roles. Table: Teams team_name: unique team name Task: Generate all valid home-away fixtures. Fixture rules: For every two different teams A and B, include: A as home, B as away B as home, A as away Do not include self fixtures where home_team equals away_team. Output requirements: Return exactly two columns: home_team, away_team Output order is not graded. Supported submission environments: SQL (SQLite 3.27.2) Pandas (Python)

Example 1

Input

Teams:
| team_name     |
|---------------|
| Harbor United |
| Metro Stars   |
| Redwood FC    |

Output

[
  {"home_team":"Harbor United","away_team":"Metro Stars"},
  {"home_team":"Harbor United","away_team":"Redwood FC"},
  {"home_team":"Metro Stars","away_team":"Harbor United"},
  {"home_team":"Metro Stars","away_team":"Redwood FC"},
  {"home_team":"Redwood FC","away_team":"Harbor United"},
  {"home_team":"Redwood FC","away_team":"Metro Stars"}
]

Explanation

Three teams produce 3 * (3 - 1) = 6 directed fixtures, with both directions included for each team pair.

Example 2

Input

Teams:
| team_name |
|-----------|
| Alpha     |
| Beta      |

Output

[
  {"home_team":"Alpha","away_team":"Beta"},
  {"home_team":"Beta","away_team":"Alpha"}
]

Explanation

With two teams, exactly two matches exist, one in each direction.

Example 3

Input

Teams:
| team_name |
|-----------|
| SoloClub  |

Output

[]

Explanation

A single team cannot play itself, so no valid fixture rows exist.

Constraints

0 <= number of rows in Teams <= 30
1 <= len(team_name) <= 30
team_name values are unique within Teams
team_name contains only letters, digits, spaces, underscore, or hyphen
Return columns exactly as: home_team, away_team
Each output row must satisfy home_team != away_team
For every unordered team pair, both directed rows must be present
For SQL submissions, use SQLite 3.27.2 semantics
For Pandas submissions, return a DataFrame with columns: home_team, away_team

Loading problem...

Preparing your editor. You can read the problem while it loads.

Double Round-Robin League Fixtures

Easy

A sports operations platform stores the participating clubs of a league season in a Teams table. The scheduling service needs a complete list of directed fixtures for a double round-robin stage, where each pair of clubs plays twice with swapped home and away roles. Table: Teams team_name: unique team name Task: Generate all valid home-away fixtures. Fixture rules: For every two different teams A and B, include: A as home, B as away B as home, A as away Do not include self fixtures where home_team equals away_team. Output requirements: Return exactly two columns: home_team, away_team Output order is not graded. Supported submission environments: SQL (SQLite 3.27.2) Pandas (Python)

Example 1

Input

Teams:
| team_name     |
|---------------|
| Harbor United |
| Metro Stars   |
| Redwood FC    |

Output

[
  {"home_team":"Harbor United","away_team":"Metro Stars"},
  {"home_team":"Harbor United","away_team":"Redwood FC"},
  {"home_team":"Metro Stars","away_team":"Harbor United"},
  {"home_team":"Metro Stars","away_team":"Redwood FC"},
  {"home_team":"Redwood FC","away_team":"Harbor United"},
  {"home_team":"Redwood FC","away_team":"Metro Stars"}
]

Explanation

Three teams produce 3 * (3 - 1) = 6 directed fixtures, with both directions included for each team pair.

Example 2

Input

Teams:
| team_name |
|-----------|
| Alpha     |
| Beta      |

Output

[
  {"home_team":"Alpha","away_team":"Beta"},
  {"home_team":"Beta","away_team":"Alpha"}
]

Explanation

With two teams, exactly two matches exist, one in each direction.

Example 3

Input

Teams:
| team_name |
|-----------|
| SoloClub  |

Output

[]

Explanation

A single team cannot play itself, so no valid fixture rows exist.

Constraints

0 <= number of rows in Teams <= 30
1 <= len(team_name) <= 30
team_name values are unique within Teams
team_name contains only letters, digits, spaces, underscore, or hyphen
Return columns exactly as: home_team, away_team
Each output row must satisfy home_team != away_team
For every unordered team pair, both directed rows must be present
For SQL submissions, use SQLite 3.27.2 semantics
For Pandas submissions, return a DataFrame with columns: home_team, away_team