day 15 use dicts

tcl's dict type is exactly what we need for this problem:
an order-preserving de-duplicated list of key-value pairs.

day15/sol.tcl

@@ -44,33 +44,12 @@ proc place {boxp lens} {
         set h [hash $label]
         set i 0
         set found 0
-        if {![info exists box($h)]} { set box($h) {} }
+        dict set box($h) $label $num
-        foreach {l n} $box($h) {
-            if {$l eq $label} {
-                lset box($h) $i+1 $num
-                set found 1
-                break
-            }
-            incr i 2
-        }
-        if {!$found} {
-            lappend box($h) $label $num
-        }
     } else {
         set label [trim $lens "-"]
         set h [hash $label]
         #puts "$lens $label $h"
-        if {[info exists box($h)]} {
+        dict unset box($h) $label
-            set i 0
-            foreach {l n} $box($h) {
-                if {$l eq $label} {
-                    #puts "removing $i from $h" 
-                    set box($h) [lreplace $box($h) $i $i+1]
-                    break
-                }
-                incr i 2
-            }
-        }
     }
 }
 
@@ -83,7 +62,7 @@ proc solve input {
     set t 0
     foreach {h elems} [array get box] {
         set slot 0
-        foreach {l n} $elems {
+        dict for {l n} $elems {
             incr slot
             incr t [expr {($h+1) * $slot * $n}]
         }