1 files changed, 87 insertions, 0 deletions
diff --git a/06/1.tcl b/06/1.tcl
new file mode 100644
index 0000000..49c41cf
--- /dev/null
+++ b/06/1.tcl
@@ -0,0 +1,87 @@
+#!/usr/bin/env tclsh
+
+set fp [open input r]
+set map ""
+while {1} {
+    set ret [gets $fp line]
+    if {$ret == -1} {
+        break
+    }
+    if {[string length $line] == 0} {
+        break
+    }
+    lappend map $line
+}
+
+proc char_at {x y} {
+    set line [lindex $::map $y]
+    return [string index $line $x]
+}
+
+set height [llength $map]
+set width [string length [lindex $map 0]]
+
+proc find_start {} {
+    for {set i 0} {$i < $::width} {incr i} {
+        for {set j 0} {$j < $::height} {incr j} {
+            if {[char_at $i $j] == "^"} {
+                return "$i $j"
+            }
+        }
+    }
+}
+
+set start_point [find_start]
+
+proc front_point {x y direction} {
+    if {$direction == "up"} {
+        return [list $x [expr {$y - 1}]]
+    } elseif {$direction == "down"} {
+        return [list $x [expr {$y + 1}]]
+    } elseif {$direction == "left"} {
+        return [list [expr {$x - 1}] $y]
+    } elseif {$direction == "right"} {
+        return [list [expr {$x + 1}] $y]
+    }
+}
+
+proc out_of_range {x y} {
+    return [expr {
+        ($x < 0) || ($x >= $::width) || ($y < 0) || ($y >= $::height)
+    }]
+}
+
+proc turn_right {direction} {
+    if {$direction == {up}} {
+        return right
+    } elseif {$direction == {down}} {
+        return left
+    } elseif {$direction == {right}} {
+        return down
+    } else {
+        return up
+    }
+}
+
+proc next_state {x y direction} {
+    set forward [front_point $x $y $direction]
+    if {[out_of_range {*}$forward]} {
+        return [list {*}$forward $direction]
+    }
+    if {[char_at {*}$forward] == {#}} {
+        set forward [front_point $x $y [turn_right $direction]]
+        return [list {*}$forward [turn_right $direction]]
+    } else {
+        return [list {*}$forward $direction]
+    }
+}
+
+set state [list {*}$start_point up]
+set visited {}
+
+while {![out_of_range {*}[lrange $state 0 1]]} {
+    dict set visited [lrange $state 0 1] {}
+    set state [next_state {*}$state]
+}
+
+puts [dict size $visited]