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
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
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