Update

2 files changed, 16 insertions, 15 deletions

diff --git a/presentation.pdf b/presentation.pdf
index d26aea2..7be01a7 100644
--- a/presentation.pdf
+++ b/presentation.pdf
diff --git a/solution.dyalog b/solution.dyalog
index 7958b28..a915386 100644
--- a/solution.dyalog
+++ b/solution.dyalog
@@ -2,30 +2,31 @@
 ]box on
 
 ⍝ Part 1
-cubes←⍎¨⊃⎕NGET'input'1
-movements←{⍵,-⍵}↓(3 3⍴4↑1)
-sides←,cubes∘.+movements
-≢sides~cubes
+cubes←⍎¨⊃⎕NGET'../input'1     ⍝ All lava cubes
+movements←{⍵,-⍵}↓(3 3⍴4↑1)    ⍝ 6 possible movements each
+sides←,cubes∘.+movements      ⍝ Sides: Cubes added to movements
+≢sides~cubes                  ⍝ Count of surface area
 
 ⍝ Part 2
-mins←(↑⌊/cubes)-1 1 1
-maxs←(↑⌈/cubes)+1 1 1
-in_boundary←{0≡+/((⍵<mins),(⍵>maxs))}
-count←0
+mins←(↑⌊/cubes)-1 1 1                 ⍝ Minimum coords (minx, miny, minz)
+maxs←(↑⌈/cubes)+1 1 1                 ⍝ Maximum coords (maxx, maxy, maxz)
+in_boundary←{0≡+/((⍵<mins),(⍵>maxs))} ⍝ Is cube within boundary?
+count←0                               ⍝ Final count of outer surface area
+
 cubes{ ⍝ https://dfns.dyalog.com/n_bfs.htm
-	0=≢⍵:count
-	head←1↑⍵ ⋄ tail←1↓⍵
-	neighbors←movements+¨head
-	next←{(in_boundary¨⍵)/⍵}neighbors
-	count⊢←count+(+/{(↓⍵)∊cubes}¨neighbors)
-	(⍺,head)∇((tail∪next)~⍺)
+	0=≢⍵:count                              ⍝ If queue empty, return count
+	head←1↑⍵ ⋄ tail←1↓⍵                     ⍝ head, tail of queue
+	neighbors←movements+¨head               ⍝ 6 neighbors: head+movements
+	next←{(in_boundary¨⍵)/⍵}neighbors       ⍝ Filter neighbors by in_boundary
+	count⊢←count+(+/{(↓⍵)∊cubes}¨neighbors) ⍝ Increment count with neighbors that are in cubes
+	(⍺,head)∇((tail∪next)~⍺)                ⍝ Recursion: (visited|head) rec (tail|next)-visited
 }↓maxs
 
 ⍝ search visualization
 _←⎕ED 'grid'
 visualize←{
 	grid⊢←(maxs+1 1 1)⍴' '
-	cubes{ ⍝ https://dfns.dyalog.com/n_bfs.htm
+	cubes{
 		0=≢⍵:count
 		head←1↑⍵ ⋄ tail←1↓⍵
 		grid[|head]⊢←'O'