day 16 cleanup

switch to globals (passing array names around is ugly).
(maybe look into dicts sometime?)

also, properly detect width/height from the input
instead of hardcoding it

day16/sol.tcl

@@ -1,8 +1,10 @@
 #!/usr/bin/env tclsh
 source ../prelude.tcl
 
-proc read-input {gridp input} {
-    upvar $gridp grid
+proc read-input {input} {
+    global grid
+    global width
+    global height
     set i 0
     while {[gets $input line] >= 0} {
         set j 0
@@ -12,25 +14,47 @@ proc read-input {gridp input} {
         }
         incr i
     }
+    set height $i
+    set width $j
 }
 
-proc mark-visited {visitp x y d} {
-    if {$x < 0} {return 0}
-    upvar $visitp visit
+proc reset-visited {} {
+    global visit
+    array unset visit
+}
+
+proc mark-visited {x y d} {
+    global visit
     set v [switch -exact -- $d n {expr 1} s {expr 2} w {expr 4} e {expr 8} default {error "invalid dir '$d'"}]
     incr visit($y,$x) 0
     set result [expr {($visit($y,$x) & $v) != 0}]
-    set visit($y,$x) [expr {$visit($y,$x)|$v}]
+    set visit($y,$x) [expr {$visit($y,$x) | $v}]
     return $result
 }
 
-proc follow {gridp visitp beams {first 0}} {
-    upvar $gridp grid
-    upvar $visitp visit
+proc print-visited {} {
+    global visit
+    global width
+    global height
+    for {set i 0} {$i < $height} {incr i} {
+        set row {}
+        for {set j 0} {$j < $width} {incr j} {
+            if {[info exist visit($i,$j)] && $visit($i,$j)} {
+                lappend row "#"
+            } else {
+                lappend row "."
+            }
+        }
+        puts [join $row ""]
+    }
+}
+
+proc follow {beams {first 0}} {
+    global grid
     set newbeams {}
     foreach {x y d} $beams {
         if {!$first} {
-            if { [mark-visited visit $x $y $d] } continue
+            if { [mark-visited $x $y $d] } continue
             switch $d {
                 n { incr y -1 }
                 s { incr y +1 }
@@ -38,48 +62,37 @@ proc follow {gridp visitp beams {first 0}} {
                 e { incr x +1 }
             }
         }
-        if {![info exists grid($y,$x)]} continue
-        switch -exact "$grid($y,$x) $d" {
-            {\ n} { set d w }
-            {\ s} { set d e }
-            {\ e} { set d s }
-            {\ w} { set d n }
-            {/ n} { set d e }
-            {/ s} { set d w }
-            {/ e} { set d n }
-            {/ w} { set d s }
-            {| w} { set d {n s} }
-            {| e} { set d {n s} }
-            {- n} { set d {w e} }
-            {- s} { set d {w e} }
-        }
-        foreach d' [split $d] {
-            lappend newbeams $x $y ${d'}
+        if {[info exists grid($y,$x)]} {
+            switch -exact "$grid($y,$x) $d" {
+                {\ n} { set d w }
+                {\ s} { set d e }
+                {\ e} { set d s }
+                {\ w} { set d n }
+                {/ n} { set d e }
+                {/ s} { set d w }
+                {/ e} { set d n }
+                {/ w} { set d s }
+                {| w} { set d {n s} }
+                {| e} { set d {n s} }
+                {- n} { set d {w e} }
+                {- s} { set d {w e} }
+            }
+            foreach d' [split $d] {
+                lappend newbeams $x $y ${d'}
+            }
         }
     }
     return $newbeams
 }
 
 proc solve {} {
-    global grid
-    set beams [follow grid visit {0 0 e} 1]
+    global visit
+    reset-visited
+    set beams [follow {0 0 e} 1]
     while {[llen $beams] > 0} {
-        set beams [follow grid visit $beams]
-    }
-    set t 0
-    set N 10
-    for {set i 0} {$i < $N} {incr i} {
-        set row {}
-        for {set j 0} {$j < $N} {incr j} {
-            if {[info exists visit($i,$j)] && $visit($i,$j)} {
-                lappend row "#"
-                incr t
-            } else {
-                lappend row "."
-            }
-        }
-        puts [join $row ""]
+        set beams [follow $beams]
     }
+    print-visited
     puts [array size visit]
 }
 
@@ -89,8 +102,13 @@ proc lmax {list} {
     return $t
 }
 
-proc solve2 {width height} {
+proc solve2 {} {
     global grid
+    global width
+    global height
+    global visit
+    puts "width=$width height=$height"
+
     set edges {}
     foreach k [array names grid] {
         lassign [split $k ","] y x
@@ -102,10 +120,10 @@ proc solve2 {width height} {
 
     set l {}
     foreach beams $edges {
-        array unset visit
-        set beams [follow grid visit $beams 1]
+        reset-visited
+        set beams [follow $beams 1]
         while {[llen $beams] > 0} {
-            set beams [follow grid visit $beams]
+            set beams [follow $beams]
         }
         puts [array size visit]
         lappend l [array size visit]
@@ -114,9 +132,10 @@ proc solve2 {width height} {
     puts [lmax $l]
 }
 
-read-input grid stdin
+read-input stdin
 puts [array get grid]
-puts [follow grid visit {0 0 e}]
+puts [follow {0 0 e}]
+puts [array get visit]
 
 solve
-solve2 110 110
+solve2