1 files changed, 71 insertions, 0 deletions
diff --git a/08/1.tcl b/08/1.tcl
new file mode 100644
index 0000000..1c4ed1d
--- /dev/null
+++ b/08/1.tcl
@@ -0,0 +1,71 @@
+set fp [open "input"]
+set lines {}
+while {[gets $fp line] >= 0} {
+    lappend lines $line
+}
+
+close $fp
+
+set height [llength $lines]
+set width [string length [lindex $lines 0]]
+
+proc char_at {x y} {
+    global lines
+    return [string index [lindex $lines $y] $x]
+}
+
+proc in_range {x y} {
+    global height width
+    if {$x < 0 || $x >= $width} {
+        return 0
+    }
+    if {$y < 0 || $y >= $height} {
+        return 0
+    }
+    return 1
+}
+
+proc build_antenna_map {} {
+    global height width
+    set antenna_map {}
+    for {set x 0} {$x < $width} {incr x} {
+        for {set y 0} {$y < $height} {incr y} {
+            set c [char_at $x $y]
+            if {$c == "."} {
+                continue
+            }
+            dict update antenna_map $c site_list {
+                lappend site_list [list $x $y]
+            }
+        }
+    }
+    return $antenna_map
+}
+
+set antenna_map [build_antenna_map]
+set antinodes {}
+
+foreach k [dict keys $antenna_map] {
+    set site_list [dict get $antenna_map $k]
+    set len [llength $site_list]
+    for {set i 0} {$i < $len} {incr i} {
+        for {set j [expr {$i + 1}]} {$j < $len} {incr j} {
+            set x1 [lindex [lindex $site_list $i] 0]
+            set y1 [lindex [lindex $site_list $i] 1]
+            set x2 [lindex [lindex $site_list $j] 0]
+            set y2 [lindex [lindex $site_list $j] 1]
+            set x3 [expr {$x1 - ($x2 - $x1)}]
+            set y3 [expr {$y1 - ($y2 - $y1)}]
+            set x4 [expr {$x2 + ($x2 - $x1)}]
+            set y4 [expr {$y2 + ($y2 - $y1)}]
+            if {[in_range $x3 $y3]} {
+                dict set antinodes [list $x3 $y3] {}
+            }
+            if {[in_range $x4 $y4]} {
+                dict set antinodes [list $x4 $y4] {}
+            }
+        }
+    }
+}
+
+puts [dict size $antinodes]