Pairwise Seat Swap Ledger

Medium

You are given a Seat table that stores the current student assigned to each seat index. Columns: id: unique seat index student: student name currently mapped to that id Data guarantees: id values are continuous integers from 1 to n (no gaps) id is unique Task: Create a reassignment ledger where every consecutive pair of seat ids is swapped: (1, 2) swap students (3, 4) swap students and so on. If n is odd, the student at the last id keeps the same id. Return the resulting table with exactly two columns: id student Return rows ordered by id in ascending order. Supported submission environments: SQL (SQLite 3.27.2) Pandas (Python)

Input

Seat:
| id | student |
|----|---------|
| 1  | Ada     |
| 2  | Ben     |
| 3  | Cara    |
| 4  | Drew    |
| 5  | Evan    |

Output

[
  {"id":1,"student":"Ben"},
  {"id":2,"student":"Ada"},
  {"id":3,"student":"Drew"},
  {"id":4,"student":"Cara"},
  {"id":5,"student":"Evan"}
]

Explanation

Pairs (1,2) and (3,4) are swapped. Because the row count is odd, id 5 remains unchanged.

Input

Seat:
| id | student |
|----|---------|
| 1  | Nina    |
| 2  | Omar    |
| 3  | Pia     |
| 4  | Quinn   |

Output

[
  {"id":1,"student":"Omar"},
  {"id":2,"student":"Nina"},
  {"id":3,"student":"Quinn"},
  {"id":4,"student":"Pia"}
]

Explanation

The total row count is even, so every row is part of exactly one swapped pair.

Input

Seat:
| id | student |
|----|---------|
| 1  | Alex    |

Output

[
  {"id":1,"student":"Alex"}
]

Explanation

A single row has no partner id to swap with, so output is unchanged.

Constraints

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