# Problem 60642. ICFP2024 010: Lambdaman Optimal-Crawler-Backfill

The ICFP2024 contest was held June29 thru July 1. The contest consisted of five parts: ICFP Language, Lambdaman maze, Starship flying, 3D - graph programming, and Efficiency - processing complex ICFP message to a numerical value.
The Lambdaman 4 maze is medium size,21x21, L near top left, '.' a cheese bit, # is Wall. Matrix uses Wall=0,L=1,Cheese=2. Encircling Walls are added to all mazes.
The contest goal was to write a minimal size, bytes, expression that moves L, Lambdaman, to eat each cheese bit.
Shown is Lambdaman4 with a best known solution is 348 U/R/D/L commands by completing the lower left before lower right. This challenge requires an Optimal Crawler-Backfill method for paths width==1 and there are no loops.
This challenge is to solve multiple Lamdaman mazes by eating all the cheese via a char path of UDLR, with a program smaller than the template. The template implements an Optimal Crawler-Backfill with recursions for speed where only one choice possible. Optimal checks all viable move directions from an intersection and selects shortest to fill. Fill smallest branch first to minimize total length. The challenge is to make a smaller optimal crawler.
Maze#/Crawler/OptimalCrawler
1/15/15 2/33/26 4/394/348 11/9988/9622 12/9992/9626 13/9976/9562 14/9994/9478 15/9986/9584
These are believed to be optimal solutions. Post in comments if any are beat.

### Solution Stats

100.0% Correct | 0.0% Incorrect
Last Solution submitted on Jul 24, 2024

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