From 547fe03cf43105f46160e2dd9afff21637eaaf47 Mon Sep 17 00:00:00 2001
From: Hunky Jimpjorps <thechairman@thechairman.info>
Date: Fri, 2 Feb 2024 17:24:30 -0500
Subject: 2018, day 1 complete

---
 aoc2018/day-01/day-01.rkt | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 aoc2018/day-01/day-01.rkt

diff --git a/aoc2018/day-01/day-01.rkt b/aoc2018/day-01/day-01.rkt
new file mode 100644
index 0000000..b18f7c9
--- /dev/null
+++ b/aoc2018/day-01/day-01.rkt
@@ -0,0 +1,16 @@
+#lang racket
+
+(require advent-of-code
+         threading)
+
+(define deltas
+  (~>> (open-aoc-input (find-session) 2018 1 #:cache #true) port->lines (map string->number)))
+
+;; part 1
+(for/sum ([delta deltas]) delta)
+
+;; part 2
+(for/fold ([seen (set)] [current-frequency 0] #:result current-frequency) ([delta (in-cycle deltas)])
+  (define new-frequency (+ current-frequency delta))
+  #:final (set-member? seen new-frequency)
+  (values (set-add seen new-frequency) new-frequency))
-- 
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