Full-height skyline columns partition the remaining board. Add sound gcd and bounded subset-sum checks for the resulting component areas, with boundary-event and periodic benchmark schedules.
Keep the rules disabled by default because their small tree reductions do not recover their measured cost. Record the rejected default and scheduling evidence so it can be revisited only with new data.
Tests: Debug CTest (14 passed)
Tests: ASan+UBSan CTest (14 passed)
Refs: #13
A skyline may retain enough total empty area while no longer containing a box for its largest remaining square. Scan for the required consecutive low columns and reject such monotonic dead states.
Keep each pruning combination independently measurable and record the small public-path gain, the direct-order-9 regression, and the rejected periodic schedule.
Tests: Debug CTest (13 passed)
Tests: ASan+UBSan CTest (13 passed)
Refs: #15
A selected valley cannot admit a square wider than itself until it reaches the lower neighbouring rim. Reject states whose remaining narrow-square area cannot fill that strip, including width-one and width-two gaps.
Keep an unpruned benchmark mode and dedicated counters so the rule remains independently measurable. Record the soundness argument and the measured default-on improvement.
Tests: Debug CTest (12 passed)
Tests: ASan+UBSan CTest (12 passed)
Refs: #10
Constrain the unique unit square to a closed D4 fundamental region once its placement is known. This preserves one representative of every board-orientation orbit without assigning identities to repeated squares.
Keep a symmetry-disabled benchmark path, document the proof and measurements, and cover generic, diagonal, midline, corner, and centre orbits.
Tests: Release, Debug, ASan, and UBSan CTest (11 passed each)
Refs: #3
Make candidate ordering an explicit deterministic policy and benchmark ascending, descending, and exact-width-first choices. Keep ascending as the default because it produces the best measured time to first solution despite best-fit's slightly smaller tree.
Retain the benchmark v1 interface and document why randomized and duplicate-work portfolio policies are deferred.
Tests: Release and Debug CTest (10 passed each)
Refs: #12
Represent partial placements as column heights and branch on the narrowest local valley. This removes the board-area cell state and makes first-solution search substantially smaller for feasible orders.
Expose direct-search and candidate-order benchmark controls so the skyline core can be measured independently of odd-order construction. Document the completeness argument and the 10/11 test-tier decision.
Tests: Release, Debug, ASan, and UBSan CTest (10 passed each)
Refs: #4
Provide a separately installed OR-Tools model to compare a generic constraint solver with the native first-solution path without adding a production or default-test dependency.
Use no-overlap, exact-fill, edge and equal-copy symmetry constraints, validate placements independently, and record model size, memory, worker count and timings for orders 8 and 9. Keep the tool only as a reference and defer DLX absent new evidence.
Tests: Release CTest (9 passed)
Tests: Python reference tests and compilation checks
Tests: independently validated CP-SAT orders 8 and 9
Refs: #5
Avoid repeating the exponential search for odd orders at least nine. Search the even predecessor, translate its row-major placements to the enlarged board, and tile the new border.
Keep direct search and construction explicit so benchmarks can report their costs separately. Verify the routed order-9 result independently and require its search counters to match order 8.
Tests: Release, Debug, ASan and UBSan CTest (8 passed each)
Refs: #6
Record reproducible order-7 and order-8 measurements from the committed benchmark framework with a clean working tree. Include stable work counts, solve-time spread, validation and rendering cost, and interleaved instrumentation overhead.
Order 9 remains supported by the runner but retains its historical timing because each current run takes several minutes.
Benchmark: Apple arm64 Release, one warm-up, three repetitions
Refs: #8
Add an opt-in benchmark probe and JSON runner that separate solve, construction, validation, and rendering time. Record stable search counters, environment metadata, warm-up and repetition policy, timeouts, errors, median spread, and instrumentation overhead.
Compile production solving without counters and interleave counted and plain trials when measuring overhead. Keep heavyweight cases outside the default correctness path while testing counter and report behavior cheaply.
Tests: Debug and Release CTest suites (7 passed each)
Refs: #8
next_pos() returns the grid end sentinel when a placement completes the board. Avoid passing that sentinel to largest_square(), which requires an in-range position and otherwise reads past the grid.
Tests: Debug, Release, ASan, and UBSan CTest suites
Refs: #14
Exercise both the trivial order-1 solution and the feasible order-8 solution through the independent placement validator.
With the existing completion ordering, the focused test reports a heap-buffer-overflow under AddressSanitizer before validation can run.
Refs: #14
Check the character in the output string instead of referring to a nonexistent grid_ member. This restores Debug compilation while preserving the intended invariant that rendering must not write an identical character twice.
Size labels intentionally replace interior spaces, so requiring an entirely unwritten destination would reject valid solutions. Update the testing notes now that Debug builds pass.
Tests: Debug and Release CTest suites (4 passed each)
Refs: #7
Exercise Results::output() with the known order-8 fixture so Debug builds compile and run the rendering assertions. Check the output dimensions and ensure the valid tiling leaves no unrendered cells.
The test passes in Release and currently fails to compile in Debug because Results::set() refers to the nonexistent grid_ member.
Refs: #7
Establish a CTest harness before changing solver behavior. Validate board dimensions, multiplicities, bounds, overlap and coverage against independent placement data, including known order-8 and constructed order-9 fixtures.
Document Debug and sanitizer workflows while keeping the defects tracked by #7 and #14 separate. Prepare a result adapter so the feasible solver regression can be enabled with the completion fix.
Tests: Release, ASan and UBSan CTest suites (3 passed each)
Refs: #1
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