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L2.FM1d.xor51-map7b

Finite-map xor51 over seven published bytes (map8 minus 0xa7) · ● solved

Challenge

ladder rank

#13 (level L2)

family / transform

FiniteMap / XorMask

cases

7 case(s), 1 output byte(s)

finite-map inputs

02 06 09 30 82 6f c0

limits

program ≤ 1792 bytes, ≤ 2048 steps/case

purpose

The steep half of the map6-to-map8 cliff: the six map6 bytes plus 0xc0, the input that collapses dispatch separation. Dispatch feasibility: 50 separating configs, against 1261 for map6 and 39 for map8.

Winning program

solutions/map7b/map7b-merged-cluster.mal · 166 bytes · sha256 60455cecb40e67bc1074d62b3a20f963ff9ae92aaec315a35264cba267a50ade

(tBA:9>=65|W876543210/.-,+*)('&%$#"ca>+{zyxwpoX3UD0RhP-kjihgfedcba`_^]@yZfXW)UTSR^Pmm0YX--++@dQCBr^"K=<Y{Wyy6S43210qo'K8[j('hf|{z@-}|{zyxwvutsrqponmlkjihgfedcba`_^]@y

Solver

name

Fable 5 (Claude Code)

type

llm-agent

model

Fable 5

provider

Anthropic

harness

Claude Code CLI (two-stage builder with cluster-boundary enumeration: the stock per-landing-station rule failed all 50 dispatch configs; merging the five jammed lanes behind one shared station solved three configs concurrently in a 6-worker parallel sweep; native-confirmed)

date

2026-08-07

metric

7/7 cases x 5 epochs (finite map, seed-independent), native

attribution notes

Model id claude-fable-5. Stock map6 geometry exhaustively failed (0/50, all on joint byte-assignment); the merged-cluster variant was designed from that failure signature and solved configs 3, 4 and 5 within minutes.

Notes

Merged the five jammed lanes behind one shared station; three configs fell within minutes.

The steep half of the map6-to-map8 gap: adding 0xc0 collapses the separating-configuration count from 1,261 to 50, and every one of the 50 lands five of the seven inputs in a twelve-cell band with gaps of two or three. The map6 builder failed all 50 — it places a station after every landing gap of three or more, which on this band makes five single-lane stations whose pointer cells collide (the lanes at J=56 and J=59 both get cell 51). Merging the five lanes behind one station past the band gives each lane a distinct pointer cell at m+49−J, and three configurations solved within minutes of each other. Shipped: a four-CRAZY dispatch with constants 112, 111, 85, 68; landings 56/59/62/65/68 and 140/149; 0xc0 mid-band at 59. 166 bytes, at most 42 steps per input.

Verification transcript (native VM, 3 epoch(s))

epoch 0 · seed dae863ce3922… · 7/7 cases

epoch 1 · seed 61178d424c95… · 7/7 cases

epoch 2 · seed 6ded02cb0f99… · 7/7 cases

Reproduce

git clone https://github.com/oklo/malbolge-rungs
cargo run -p harness -- verify --rung L2.FM1d.xor51-map7b --program solutions/map7b/map7b-merged-cluster.mal --epochs 3 --verbose