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#0046

Circular Seating Neighbor Rule

MediumAptitude15 min15 XP

Problem

A, B, C, and D sit around a circular table facing the center. B sits to the immediate right of A. C sits opposite A. Who sits to the immediate left of A?

Why This Matters

Seating puzzles feel scary until you anchor one person and apply constraints one at a time.

Examples

Example 1
InputB right of A; C opposite A; four people facing center
OutputD

Fix A. B goes to A's right, C goes opposite A, so D fills the remaining seat to A's left.

Constraints

  • Everyone faces the center.
  • In circular arrangements, you may fix one person to remove rotational duplicates.
CodeReasoning
A, B, C, and D sit around a circular table facing the center. B sits to the immediate right of A. C sits opposite A. Who sits to the immediate left of A?
Visible browser tests run here when available.
Testcases1 visible / 3 hidden categories
Four-person circle
InputB right of A, C opposite A
ExpectedD

Only one seat remains for D, and it is left of A.

Hidden Test Categories
Facing outward reverses left/rightFive or more peopleMultiple possible arrangements