Algorithm X

Who Dunnit?

Puzzle: Who Dunnit? Awaiting Approval - See CG Contribution Page

Author: @David Augusto Villa

Published Difficulty: Hard

Algorithm X Complexity: Well-Hidden Exact Cover, but Straightforward Setup

Strategy

Spoiler Alert: This puzzle is an exact cover problem.

Why do I feel the need to issue that spoiler alert? I believe the hardest part of this puzzle is figuring out that it is, indeed, an exact cover problem. The exact cover is very cleverly hidden by both the structure of the puzzle and the author’s instructions, but it is there, and once you see it, setting up Algorithm X becomes straightforward.

Hopefully, the requirements are jumping out at you. One clue must be identified from each set of evidence. The next steps get a bit more difficult.

The most important part of solving this puzzle with Algorithm X will be how you choose to model the problem as tiles on a gameboard. What are the tiles? What does the gameboard look like? Ultimately, you need to identify a culprit, but how are you placing tiles on a gameboard to get to a place where the culprit is easily identified?

What do I mean by “cleverly hidden”? My tiles on a gameboard analogy went through 4 iterations before I felt like I truly understood how to best model the task at hand. That alone is another spoiler: if you are stuck, try to find other ways of looking at your tiles on a gameboard analogy.