aoc2022d9

      ⎕VR 'foo'
     ∇ hist←foo ins;head;end;m
[1]    hist←⊂0 0              
[2]    head←0 0               
[3]    end←0 0                
[4]    :For m :In ins         
[5]        head+←m            
[6]        :If ∨/2≤|head-end  
[7]            end+←×head-end 
[8]            hist,←⊂end     
[9]        :EndIf             
[10]   :EndFor                
[11]   hist←∪hist             
     ∇                        
      ⎕VR 'foo2'
     ∇ hist←foo2 ins;ends;m;i;d                
[1]    hist←⊂0 0                               
[2]    ends←10/(⊂0 0)                          
[3]    :For m :In ins                          
[4]        (1⊃ends)+←m                         
[5]        :For i :In ⍳9                       
[6]            :If ∨/2≤|d←(i⊃ends)-((1+i)⊃ends)
[7]                ((1+i)⊃ends)+←×d            
[8]            :EndIf                          
[9]        :EndFor                             
[10]       hist,←⊂10⊃ends                      
[11]   :EndFor                                 
[12]   hist←∪hist                              
     ∇
      ⎕VR 'ins'
     ∇ ins←{               
[1]        n←⊃(//)⎕VFI ⍵   
[2]        'R'=⊃⍵:n/(⊂0 1) 
[3]        'L'=⊃⍵:n/(⊂0 ¯1)
[4]        'U'=⊃⍵:n/(⊂1 0) 
[5]        'D'=⊃⍵:n/(⊂¯1 0)
[6]    }
     ∇
     data←⊃,/ins¨⊃⎕NGET'input.txt'1
     ⊢part1←⍴foo data
     ⊢part2←⍴foo2 data