FA-81947 / Poker hand evaluation / Member archive

Four-card run accepted as a straight · case 02

9-T-J-Q with no eight or king is reported as a queen-high straight.

Member previewVariant 2 · 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
four-straight only	`12`	`0`	Failed

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