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Weak heap ancestor cost counts only orientation-driven climbs · case 03

The bounded weak ancestor certificate reports an incorrect cost.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

A weak heap stores reverse bits r in a zero-based array. For nonroot node j, climb while j is a left child under its parent reverse bit: (j mod 2)==r[j//2]. Its distinguished ancestor is j//2 after climbing; zero has none. Report ancestor, climb path, climb count, stopping child, orientation bit, and whether direct parent suffices.

Why this case matters

This isolates an internal heap representation or priority-structure invariant using deterministic finite records.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression certificate 2	`{"ancestor": 0, "cost": 1, "direct": true, "orientation": 0, "path": [], "stop": 1}`	`{"ancestor": 0, "cost": 0, "direct": true, "orientation": 0, "path": [], "stop": 1}`	Failed

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