Sourav Hota — R45-T023: Cross-check MirrorOfMatrix (MirrorOfMatrix.java) [src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java] #23

Student: Sourav Hota

Task: R45-T023 · 3 of 10
Repository: https://github.com/S-AI-Projects/TheAlgorithms-Java
Assigned working branch: student/e26b07f0855

Goal

Work on src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java. Compare MirrorOfMatrix against a small independent reference for the same domain. Check dimensions and independently calculated cell values; avoid applying square-matrix rules to rectangular inputs. Fixture: Use a small rectangular matrix when supported, a 1×1 matrix, and a zero-containing matrix. For determinant([[1,2],[3,4]]) the result is -2; use that only for a determinant interface.

Steps

1. Read src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java, especially MirrorOfMatrix near line 20. Record its public inputs, result, mutation behavior and any external dependencies before changing it.
2. Write the simplest independently understandable oracle for small inputs, or calculate a fixed expected-result table when an oracle would duplicate the same algorithm.
3. Enumerate at least 20 small valid inputs (or the entire domain if smaller) and compare outputs, ignoring only ordering the contract explicitly leaves unspecified.
4. Implement work/R45-T023/check.py as a focused runner that executes the new checks and propagates failures. Native check to incorporate: mvn test (JDK 21 as specified in pom.xml); use JUnit in the corresponding src/test/java package. Record the actual command and nonzero test count.
5. Create the checks specified below and run python3 work/R45-T023/check.py. Save inputs, expected versus actual results and tool versions in work/R45-T023/; a check must exit non-zero when an assertion fails.
6. Commit the repository change on branch R45-T023; prepare a PR to the organisation fork explaining the result and linking the checks. Keep each task independently reviewable. Remove work/R45-T023/ from a later upstream branch.

Done when

☐ The checked behavior is tied to MirrorOfMatrix in src/main/java/com/thealgorithms/matrix/MirrorOfMatrix.java; every assertion has an explicit expected value.
☐ Use a small rectangular matrix when supported, a 1×1 matrix, and a zero-containing matrix. For determinant([[1,2],[3,4]]) the result is -2; use that only for a determinant interface.
☐ Existing supported behavior and the public interface are preserved unless a failing regression demonstrates and documents a defect.
☐ The oracle uses a different method or a reviewed explicit result table; it does not call the function under test.
☐ A mismatch is reduced to a minimal reproducible case and documented before any fix.

Submission checklist

• Complete this task and its checks.
• Add the required evidence and link your pull request here.
• Select this S-AI-Projects fork as the PR base repository.
• Request instructor review.

Keep this PR focused on this task. Do not submit assignment PRs to the upstream repository.