A constraint puzzle asks you to find assignments that satisfy several rules simultaneously. Each clue removes possibilities. A systematic record helps you avoid forgetting an earlier restriction while using a later one.
Start with a small assignment
Ava, Ben and Cora each have one different color: red, blue or green. Ava is not red. Ben is not blue or green. Cora is not blue. Which color belongs to each person?
Ben must be red because his other two options are excluded. Ava can no longer be red and therefore has blue or green. Cora cannot be blue or red, so Cora is green. Ava is blue.
| Person | Final color | Decisive information |
|---|---|---|
| Ben | Red | Blue and green excluded |
| Cora | Green | Blue excluded; red already used |
| Ava | Blue | Only remaining color |
Use the strongest clue first
Ben's clue immediately leaves one option. Beginning there produces more progress than repeatedly considering Ava's two possibilities. Look for a row or column with only one available assignment.
When a category is one-to-one, assigning an option to one person removes it from the others. That propagation is part of the logic, not an extra assumption—provided the question explicitly states the one-to-one rule.
Do not invent uniqueness
If the clues leave two complete arrangements, the puzzle may ask what could be true rather than demand a unique assignment. Test the wording. One solution is not evidence that no other solution exists.
A reliable finishing check
Read each clue against the final arrangement and verify the overall rules: no duplicate assignments, no missing person and no violated exclusion. If you used a temporary guess, make sure every consequence follows consistently.
This approach scales to schedules, matching tasks and seating puzzles. The underlying skill is keeping the permitted possibilities explicit while each new clue narrows them.