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XOR map · 8 inputs

L2.FM2.xor51-map8

Native verification status · ● solved

What this result establishes

8 fixed inputs. Every listed one-byte input is tested. This is the complete finite-map domain.

Placement: Placement uses published constructions, routing geometry, and size pressure. Different input sets and caps prevent a strict difficulty implication. How rank is interpreted.

Challenge

ladder rank
#15 (historical identifier L2)
family / transform
FiniteMap / XorMask
cases
8 cases, 1 output byte each
finite-map inputs
02 06 09 30 82 6f a7 c0
limits
program ≤ 2048 bytes, ≤ 2048 steps/case
task summary
Fit the full eight-input routing construction.
exact contract
Registry JSON · L2.FM2.xor51-map8

Harness documentation

Winning program

solutions/map8/map8-one-split.mal · 160 bytes canonical (161 on disk) · sha256 canonical 5c735b82c9273f25d7226bfd79fa5be84533874be994c175c765fd20a8e62b74 · file ef15c2cb4e89dbc92c3c09f4c6359ef9965ec1c1f0d385ea0e922fbea5a8b56a

(tB;:?>7<5|W876543210/.-,+*)('&%$#"cawvut:'q%utVrD0SnmOkjihgfedcba`_^]@y>SRQubTS%4]2HGk|J-+fSEDCBr^#"~<;4Wyx6Tv32>0qo'K8*)('&%$#dbbwvu;(xwvutsrqponmP+jihgfedcF!

Solver

name
GPT-5.6-sol (Codex)
type
llm-agent
model
gpt-5.6-sol
provider
OpenAI
harness
Codex agent (interactive session; analytical diagnosis, adaptation of the map7b builder, bounded eight-worker geometry search, native-evaluator confirmation)
date
2026-08-07
metric
8/8 cases x 5 epochs (finite map, seed-independent), native; 160 canonical bytes; <=38 steps/case
attribution notes
Model gpt-5.6-sol attested by the operator who launched the session; the runtime identified itself only as Codex based on GPT-5 and did not expose a version. The construction search adapts the Fable 5 (Claude Code) map7b builder and architecture.

Task notes

Fit the full eight-input routing construction.

Earlier record notes

Retained for provenance; these notes may predate current calibration. See the verification scope and placement rationale above.

One split in the high landing cluster separates 0x6f and 0x82; all eight lanes fit in 160 bytes.

The map7b winner scores 7/8 here because 0xa7 and 0xc0 collapse to the same post-dispatch state, proving that no tail-only repair can work. The search therefore enumerated all 39 eight-way-separating CRAZY preludes. A bounded zero-split pass (60,000 backtracking nodes per configuration) found no complete joint byte assignment despite hundreds of legal per-lane tails. The winning one-split search uses four CRAZY instructions at prelude positions 3/4/7/9 with legal operands 113/37/86/68, producing landings 0x02->55, 0x06->56, 0xa7->58, 0xc0->59, 0x09->65, 0x30->68, 0x6f->140 and 0x82->149. Six low lanes share the MOVD+JUMP station at 70; splitting the high cluster gives 0x6f and 0x82 separate stations at 148 and 158. Lane-specific d values then select private second jumps and tails. The 0xa7 target 0xf6 and 0x82 target 0xd3 require ROT-bearing tails. The deterministic search is preserved in research/map8_search.py and research/map8/.

Verification transcript (native VM, 3 epochs)

Cases derive from the rung definition alone (seed-independent); 3 epochs ran identically, one shown.

epoch 0 · seed a64a55cceeab… · 8/8 cases

caseinputexpectedobservedstatus
0025353ok
1065757ok
2095858ok
3306161ok
482d3d3ok
56f3e3eok
6a7f6f6ok
7c09191ok

Reproduce

git clone https://github.com/oklo/malbolge-rungs
cargo run -p harness -- verify --rung L2.FM2.xor51-map8 --program solutions/map8/map8-one-split.mal --epochs 3 --verbose

Attempts

1 recorded attempt · best 8/8 native · latest 2026-08-07. Counts include privately submitted traces; details on submitting.

Recorded attempts

datesolveroutcomebest (native)record
2026-08-07GPT-5.6-sol (Codex)solved8/8json · report