aoc2022d12

      ⎕CR 'part2'
 res←part2 map;n;p;i;e;x;hist    
 p←path height map               
 e←1=height map                  
 i←{'E'=⍵}map                    
 hist←i                          
 x←0                             
Loop:                            
 x+←1                            
 hist⌈←x×i                       
 i←(∨/({mask/,⍵}⌺3 3⊢i)∧p)∧~×hist
 →(0=+/,i)/Err                   
 →(∨/,i∧e)⍴End                   
 →Loop                           
End:                             
 res←x                           
 →0                              
Err:                             
 'Error'                         
 x                               
 res←hist                        
      ⎕cr 'path'
 path←{{(b<c)∨1≥|(b←mask/,⍵)-c←center/,⍵}⌺3 3⊢10+⍵}
      ⎕cr 'height'
 height←{26@(28∘=)1@(27∘=)((⎕C ⎕A),'SE')⍳⍵}
      mask
0 1 0 1 0 1 0 1 0
      center
0 0 0 0 1 0 0 0 0