From f31e2ea3f34f85f5513dac02f04656085347c09e Mon Sep 17 00:00:00 2001
From: haskal <haskal@bepis.xyz>
Date: Tue, 3 Dec 2019 01:05:12 -0500
Subject: [PATCH] haskal seriously this is the worst code i have ever seen

---
 3.rkt | 161 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 3.rkt

diff --git a/3.rkt b/3.rkt
new file mode 100644
index 0000000..0b57f29
--- /dev/null
+++ b/3.rkt
@@ -0,0 +1,161 @@
+#lang racket
+
+(define (parse-wire s)
+  (map parse-seg (string-split (string-trim s) ",")))
+
+(define wire-defs
+       (string-split (string-trim (file->string "input.3.txt")) "\n"))
+
+(define-struct seg (dir len))
+(define-struct aseg (x1 y1 x2 y2))
+(define-struct pt (x y))
+
+(define (pa a) (list (aseg-x1 a) (aseg-y1 a) (aseg-x2 a) (aseg-y2 a)))
+(define (pp p) (list (pt-x p) (pt-y p)))
+
+(define (parse-seg str)
+  (make-seg
+   (string->symbol (substring str 0 1))
+   (string->number (substring str 1))))
+
+(define wires (map parse-wire wire-defs))
+
+(define (make-norm-aseg x1 y1 x2 y2)
+  (let ([nx1 (min x1 x2)]
+        [nx2 (max x1 x2)]
+        [ny1 (min y1 y2)]
+        [ny2 (max y1 y2)])
+    (make-aseg nx1 ny1 nx2 ny2)))
+
+(define (seg->aseg seg x y)
+  (let ([dx (* (seg-len seg)
+               (match (seg-dir seg)
+                 ['R 1]
+                 ['L -1]
+                 [_ 0]))]
+        [dy (* (seg-len seg)
+               (match (seg-dir seg)
+                 ['U 1]
+                 ['D -1]
+                 [_ 0]))])
+        (values (make-norm-aseg x y (+ x dx) (+ y dy)) (+ x dx) (+ y dy))))
+
+(define (wire->asegwire wire)
+  (define (wire->asegwire+ wire x y)
+    (cond
+      [(empty? wire) '()]
+      [else (let-values ([(aseg newx newy) (seg->aseg (first wire) x y)])
+              (cons aseg (wire->asegwire+ (rest wire) newx newy)))]))
+  (wire->asegwire+ wire 0 0))
+
+(define aseg-wires (map wire->asegwire wires))
+
+(define (horiz? aseg)
+  (= (aseg-y1 aseg) (aseg-y2 aseg)))
+(define (vert? aseg)
+  (= (aseg-x1 aseg) (aseg-x2 aseg)))
+
+(define (cross aseg1 aseg2)
+  (cond
+    ;; both horizontal
+    [(and (horiz? aseg1) (horiz? aseg2) (= (aseg-y1 aseg1) (aseg-y1 aseg2))
+          (>= (aseg-x2 aseg2) (aseg-x1 aseg1))
+          (<= (aseg-x1 aseg2) (aseg-x2 aseg1)))
+     (list (make-pt (max (aseg-x1 aseg1) (aseg-x1 aseg2)) (aseg-y1 aseg1))
+           (make-pt (min (aseg-x2 aseg1) (aseg-x2 aseg2)) (aseg-y1 aseg1)))]
+    ;; both vertical
+    [(and (vert? aseg1) (vert? aseg2) (= (aseg-x1 aseg1) (aseg-x1 aseg2))
+          (>= (aseg-y2 aseg2) (aseg-y1 aseg1))
+          (<= (aseg-y1 aseg2) (aseg-y2 aseg1)))
+     (list (make-pt (aseg-x1 aseg1) (max (aseg-y1 aseg1) (aseg-y1 aseg2)))
+           (make-pt (aseg-x1 aseg1) (min (aseg-y2 aseg1) (aseg-y2 aseg2))))]
+    ;; h/v
+    [(and (horiz? aseg1) (vert? aseg2)
+          (>= (aseg-x1 aseg2) (aseg-x1 aseg1))
+          (<= (aseg-x1 aseg2) (aseg-x2 aseg1))
+          (>= (aseg-y1 aseg1) (aseg-y1 aseg2))
+          (<= (aseg-y1 aseg1) (aseg-y2 aseg2)))
+     (list (make-pt (aseg-x1 aseg2) (aseg-y1 aseg1)))]
+    ;; v/h
+    [(and (vert? aseg1) (horiz? aseg2)
+          (>= (aseg-x1 aseg1) (aseg-x1 aseg2))
+          (<= (aseg-x1 aseg1) (aseg-x2 aseg2))
+          (>= (aseg-y1 aseg2) (aseg-y1 aseg1))
+          (<= (aseg-y1 aseg2) (aseg-y2 aseg1)))
+     (list (make-pt (aseg-x1 aseg1) (aseg-y1 aseg2)))]
+    [else '()]))
+
+(define (aseg-cross aseg wire)
+  (cond
+    [(empty? wire) '()]
+    [else
+     (append (cross aseg (first wire)) (aseg-cross aseg (rest wire)))]))
+
+(define (get-crossings+ wire1 wire2)
+  (cond
+    [(empty? wire1) '()]
+    [else (append (aseg-cross (first wire1) wire2) (get-crossings (rest wire1) wire2))]))
+
+(define (get-crossings wire1 wire2)
+  (filter (lambda (p) (not (and (zero? (pt-x p)) (zero? (pt-y p)))))
+          (get-crossings+ wire1 wire2)))
+
+(define crossings (get-crossings (first aseg-wires) (second aseg-wires)))
+
+(define (manhattan pt)
+  (+ (abs (pt-x pt)) (abs (pt-y pt))))
+
+(define (min-crossing crs)
+  (cond
+    [(empty? crs) +inf.0]
+    [else (min (manhattan (first crs)) (min-crossing (rest crs)))]))
+
+;; Part 1
+;; Holy SHIT i cannot believe this was actually the right answer WTF
+;; i assumed i made some sort of typo in cross lol
+;; UPDATE:
+;; i had a bug where i forgot to have make-norm-aseg actually work
+;; and THEN i also forgot to filter crossing '(0 0)
+;; BUT this somehow didn't affect the answer for part 1
+;; i just got screwed on part 2
+;; anyway now both work
+(displayln (min-crossing crossings))
+
+(define (aseg-on-pt aseg pt)
+  (or
+   (and (= (pt-x pt) (aseg-x1 aseg) (aseg-x2 aseg))
+        ;; yeah so i remembered that <= can take more than 2 args here
+        ;; way before writing (cross)
+        ;; huge oof
+        (<= (aseg-y1 aseg) (pt-y pt) (aseg-y2 aseg)))
+   (and (= (pt-y pt) (aseg-y1 aseg) (aseg-y2 aseg))
+        (<= (aseg-x1 aseg) (pt-x pt) (aseg-x2 aseg)))))
+
+(define (aseg-pt-dist aseg pt)
+  (cond
+    [(horiz? aseg) (- (pt-x pt) (aseg-x1 aseg))]
+    [(vert? aseg) (- (pt-y pt) (aseg-y1 aseg))]))
+
+(define (aseg-len aseg)
+  (+
+   (- (aseg-x2 aseg) (aseg-x1 aseg))
+   (- (aseg-y2 aseg) (aseg-y1 aseg))))
+
+(define (get-steps wire pt)
+  (cond
+    [(empty? wire) (error "thinking")]
+    [else
+     (cond
+       [(aseg-on-pt (first wire) pt)
+        (aseg-pt-dist (first wire) pt)]
+       [else
+        (+ (aseg-len (first wire)) (get-steps (rest wire) pt))])]))
+
+(define (min-len-crossing crs wire1 wire2)
+  (cond
+    [(empty? crs) +inf.0]
+    [else (min (+ (get-steps wire1 (first crs)) (get-steps wire2 (first crs)))
+               (min-len-crossing (rest crs) wire1 wire2))]))
+
+;; Part 2
+(displayln (min-len-crossing crossings (first aseg-wires) (second aseg-wires)))
\ No newline at end of file