Exchange Seats
A medium-tier problem at 73% community acceptance, tagged with Database. Reported in interviews at Capgemini and 0 others.
Exchange Seats is a database problem that looks deceptively simple until you hit the actual logic. You're swapping seat assignments based on ID, and the trap is handling odd-numbered rows without a partner. It's been asked at Capgemini and sits at a 73% acceptance rate, which signals the solution is straightforward once you see the pattern, but the execution stumbles candidates who overthink the window function or miss the modulo logic. If this lands in your assessment and you blank on the approach, StealthCoder solves it invisibly in seconds.
Companies that ask "Exchange Seats"
Exchange Seats is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoderThe core trick here is using modulo arithmetic to identify odd and even IDs, then swapping them. Most candidates either write brittle conditional logic or try to join the table to itself without a clean pairing rule. The database approach uses CASE statements or window functions to shift the ID by 1, with a critical edge case: the last row, if it's odd-numbered, stays in place. The real win is recognizing you don't need a second table or complex subqueries. A single SELECT with a CASE statement that compares ID modulo 2 and handles the total row count is the move. If you're stuck mid-OA and can't recall the exact syntax for this pattern, StealthCoder renders a working solution so you keep moving.
Pattern tags
You know the problem.
Make sure you actually pass it.
Exchange Seats recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Exchange Seats interview FAQ
Is Exchange Seats still asked at major companies?+
Yes. Capgemini has been confirmed to ask it. A 73% acceptance rate suggests it's actively used as a screening filter, not archived. Database questions are cyclical in hiring, especially for roles involving data pipelines or backend infrastructure. Plan to know this one.
What's the main trick to solving this problem?+
Modulo arithmetic and conditional swapping. Use ID % 2 to identify odd and even rows, then shift IDs forward or backward by 1. The catch is the last row: if its ID is odd, it has no partner and stays put. Window functions or CASE statements handle this cleanly.
Why do candidates fail this problem?+
Overcomplicating the join logic or forgetting the edge case for odd-numbered final rows. Some write hardcoded conditionals that don't scale. Others misunderstand how to pair IDs without a separate lookup table. The solution is simpler than the mental model suggests.
Is this a SQL or relational algebra problem?+
Pure SQL. You're working with a single table and standard SQL functions like CASE, MOD, and ORDER BY. No joins or complex subqueries required. Most platforms use MySQL, PostgreSQL, or similar standard databases.
How does this relate to other database problems I should know?+
It's a stepping stone to window function problems and conditional aggregation. If you're solid on CASE statements and modulo logic, you'll handle grouping and ranking questions faster. It's foundational SQL thinking, not advanced, but the pattern appears often.
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