Input: an n×m matrix whose entries are author identifiers in the range 1 through k.
Operation: choose a position (i, j). This deletes the chosen encyclopedia and every other encyclopedia written by that author that lies in row i or column j.
Output: determine the fewest cell choices required to delete all encyclopedias.
Notes
Since the complete bounds are unavailable, first establish the limits for n, m, and k before deciding among exhaustive search, matching/cover models, or solving separately by author.
Deletion applies only to the selected author: choosing a cell for author a affects no cells belonging to other authors, even when they share its row or column.
This prompt appeared alongside Process Starvation Time, which was presented as the more difficult 2026 Engineering OA problem.