solve advent of code 2023 06 part1

2 files changed, 35 insertions, 0 deletions

diff --git a/advent-of-code/2023/06/1.rkt b/advent-of-code/2023/06/1.rkt
new file mode 100644
index 0000000..ea0d013
--- /dev/null
+++ b/advent-of-code/2023/06/1.rkt
@@ -0,0 +1,32 @@
+#lang racket
+
+(define in (open-input-file "input"))
+
+(define (read-num-list)
+   (define line (read-line in))
+   (map
+       string->number
+       (string-split
+           (cadr (string-split (string-trim line) ":")))))
+
+(define times (read-num-list))
+(define distances (read-num-list))
+
+(define games (map cons times distances))
+
+(define (calc time hold-time)
+    (* hold-time (- time hold-time)))
+
+(define (solve time distance)
+    (define (loop counter hold-time)
+        (if (> hold-time time)
+            counter
+            (if (> (calc time hold-time) distance)
+                (loop (+ 1 counter) (+ 1 hold-time))
+                (loop counter (+ 1 hold-time)))))
+    (loop 0 0))
+
+(display (apply * (map 
+                     (lambda (x) (solve (car x) (cdr x)))
+                     games)))
+(newline)
diff --git a/advent-of-code/2023/06/input b/advent-of-code/2023/06/input
new file mode 100644
index 0000000..41dd40b
--- /dev/null
+++ b/advent-of-code/2023/06/input
@@ -0,0 +1,3 @@
+Time:        59     70     78     78
+Distance:   430   1218   1213   1276
+