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Description

Editorial

Three-School Unique Delegate Triplets

EASY10 pts

A national student leadership council is assembling a three-member delegation.

Table: school_a

student_id: unique identifier within School A
student_name: unique name within School A

Table: school_b

student_id: unique identifier within School B
student_name: unique name within School B

Table: school_c

student_id: unique identifier within School C
student_name: unique name within School C

Each delegate team must include exactly:

one student from school_a,
one student from school_b,
one student from school_c.

A team is valid only if all three selected IDs are pairwise different and all three selected names are pairwise different.

Task: Return every valid team as (member_a, member_b, member_c), where each member column is the selected student_name from the corresponding school.

Output requirements:

Return exactly three columns in this order:
- member_a
- member_b
- member_c
Sort by member_a, member_b, member_c in ascending order.

Supported submission environments:

SQL (SQLite 3.27.2)
Pandas (Python)

Example

Input

school_a:
| student_id | student_name |
|------------|--------------|
| 1          | Alice        |
| 2          | Bob          |

school_b:
| student_id | student_name |
|------------|--------------|
| 3          | Tom          |

school_c:
| student_id | student_name |
|------------|--------------|
| 3          | Tom          |
| 2          | Jerry        |
| 10         | Alice        |

Output

[
  {"member_a":"Alice","member_b":"Tom","member_c":"Jerry"},
  {"member_a":"Bob","member_b":"Tom","member_c":"Alice"}
]

Explanation

Triplets with repeated names or repeated IDs across selected members are rejected. Only the two shown combinations satisfy both pairwise-distinct constraints.

Example

Input

school_a:
| student_id | student_name |
|------------|--------------|
| 11         | Zara         |

school_b:
| student_id | student_name |
|------------|--------------|
| 22         | Liam         |

school_c:
| student_id | student_name |
|------------|--------------|
| 33         | Noor         |

Output

[
  {"member_a":"Zara","member_b":"Liam","member_c":"Noor"}
]

Explanation

There is exactly one possible triplet and both IDs and names are mutually distinct, so it is valid.

Example

Input

school_a:
| student_id | student_name |
|------------|--------------|
| 5          | Iris         |
| 6          | Owen         |

school_b:
| student_id | student_name |
|------------|--------------|
| 5          | Miko         |
| 8          | Iris         |

school_c:
| student_id | student_name |
|------------|--------------|
| 6          | Dana         |
| 9          | Miko         |

Output

[
    {"member_a":"Owen","member_b":"Iris","member_c":"Miko"}
]

Explanation

Most combinations fail because of either ID collisions (for example A.id=6 with C.id=6) or name collisions (for example B.name=Miko with C.name=Miko). Only one triplet satisfies all six pairwise checks.

Accepted0/0·0% Acceptance

Constraints

0 <= number of rows in each of school_a, school_b, school_c <= 80
1 <= student_id <= 1000000000
student_id is unique within each individual school table
student_name is unique within each individual school table
student_name is a non-empty string with reasonable length
Cross-school overlaps of IDs and names are allowed in input
A valid output triplet must satisfy pairwise distinct IDs and pairwise distinct names
Return exactly columns: member_a, member_b, member_c
Sort output by member_a, member_b, member_c ascending
Use SQLite 3.27.2 semantics for SQL submissions
For Pandas submissions, return a DataFrame with exact columns: member_a, member_b, member_c

Code

Visualizer

Solutions

14px

Test Cases3

Results

Submissions

school_a =

[{"student_id":101,"student_name":"Rhea"}]

school_b =

[{"student_id":201,"student_name":"Kian"}]

school_c =

[]

Three-School Unique Delegate Triplets

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Three-School Unique Delegate Triplets

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