FA-81940 / Poker hand evaluation / Member archive

Ace mirrored into the wrong low bit · case 05

A-2-3-4-5 in a seven-card hand is not found as a straight.

Member previewVariant 5 · 3 implementations · 8 checks per implementation

Case contract

Input: 5 to 7 distinct cards "Rs". Build a rank bitmask (bit r for rank value r, 2..14; the ace also sets bit 1). Return the top rank of the highest five-card straight contained in the ranks (5 for the wheel), or 0 if none.

Why this case matters

Bitmask evaluators are the standard fast path for seven-card hold'em straights.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
wheel in seven	`0`	`5`	Failed

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