From 35112ef68dd1b32a30f875d68b31df47f469cd7b Mon Sep 17 00:00:00 2001
From: xenia <xenia@awoo.systems>
Date: Sun, 4 Dec 2022 00:24:29 -0500
Subject: [PATCH] day 4: make it fancey

---
 4.rkt | 30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/4.rkt b/4.rkt
index 047a55c..4f10c23 100644
--- a/4.rkt
+++ b/4.rkt
@@ -1,32 +1,26 @@
 #lang curly-fn racket
 
-(require "scripts/aoc.rkt")
+(require "scripts/aoc.rkt"
+         (prefix-in is: data/integer-set))
 
 ;; solution for day 4
 
 (define (part1 input)
-  (for/sum ([line (in-list input)])
-    (match-define (list (cons a b) (cons c d)) line)
-    (if (or (and (>= a c) (<= b d))
-            (and (>= c a) (<= d b)))
-      1 0)))
+  (for*/sum ([line (in-list input)]
+             [u (in-value (apply is:union line))]
+             #:when (member u line))
+    1))
 
 (define (part2 input)
-  (for/sum ([line (in-list input)])
-    (match-define (list (cons a b) (cons c d)) line)
-    (if (or (and (>= a c) (<= a d))
-            (and (>= c a) (<= c b))
-            (and (>= b c) (<= b d))
-            (and (>= d a) (<= d b)))
-      1 0)))
+  (for*/sum ([line (in-list input)]
+             [i (in-value (apply is:intersect line))]
+             #:unless (zero? (is:count i)))
+    1))
 
 (define (parse fname)
   (for/list ([line (in-list (file->lines fname))])
-    (match-define (list l r) (string-split line ","))
-    (match-define (list a b) (string-split l "-"))
-    (match-define (list c d) (string-split r "-"))
-    (list (cons (string->number a) (string->number b))
-          (cons (string->number c) (string->number d)))))
+    (map #{~>> (string-split % "-") (map string->number) (apply is:make-range)}
+         (string-split line ","))))
 
 (module+ main
   (define input (parse "inputs/4"))