1623. All Valid Triplets That Can Represent a Country π
Description
Table: SchoolA
+---------------+---------+ | Column Name | Type | +---------------+---------+ | student_id | int | | student_name | varchar | +---------------+---------+ student_id is the column with unique values for this table. Each row of this table contains the name and the id of a student in school A. All student_name are distinct.
Table: SchoolB
+---------------+---------+ | Column Name | Type | +---------------+---------+ | student_id | int | | student_name | varchar | +---------------+---------+ student_id is the column with unique values for this table. Each row of this table contains the name and the id of a student in school B. All student_name are distinct.
Table: SchoolC
+---------------+---------+ | Column Name | Type | +---------------+---------+ | student_id | int | | student_name | varchar | +---------------+---------+ student_id is the column with unique values for this table. Each row of this table contains the name and the id of a student in school C. All student_name are distinct.
There is a country with three schools, where each student is enrolled in exactly one school. The country is joining a competition and wants to select one student from each school to represent the country such that:
member_A
is selected fromSchoolA
,member_B
is selected fromSchoolB
,member_C
is selected fromSchoolC
, and- The selected students' names and IDs are pairwise distinct (i.e. no two students share the same name, and no two students share the same ID).
Write a solution to find all the possible triplets representing the country under the given constraints.
Return the result table in any order.
The result format is in the following example.
Example 1:
Input: SchoolA table: +------------+--------------+ | student_id | student_name | +------------+--------------+ | 1 | Alice | | 2 | Bob | +------------+--------------+ SchoolB table: +------------+--------------+ | student_id | student_name | +------------+--------------+ | 3 | Tom | +------------+--------------+ SchoolC table: +------------+--------------+ | student_id | student_name | +------------+--------------+ | 3 | Tom | | 2 | Jerry | | 10 | Alice | +------------+--------------+ Output: +----------+----------+----------+ | member_A | member_B | member_C | +----------+----------+----------+ | Alice | Tom | Jerry | | Bob | Tom | Alice | +----------+----------+----------+ Explanation: Let us see all the possible triplets. - (Alice, Tom, Tom) --> Rejected because member_B and member_C have the same name and the same ID. - (Alice, Tom, Jerry) --> Valid triplet. - (Alice, Tom, Alice) --> Rejected because member_A and member_C have the same name. - (Bob, Tom, Tom) --> Rejected because member_B and member_C have the same name and the same ID. - (Bob, Tom, Jerry) --> Rejected because member_A and member_C have the same ID. - (Bob, Tom, Alice) --> Valid triplet.
Solutions
Solution 1
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