solve advent of code 2023 06 part2

1 files changed, 29 insertions, 0 deletions

diff --git a/advent-of-code/2023/06/2.rkt b/advent-of-code/2023/06/2.rkt
new file mode 100644
index 0000000..5d124e0
--- /dev/null
+++ b/advent-of-code/2023/06/2.rkt
@@ -0,0 +1,29 @@
+#lang racket
+
+(define in (open-input-file "input"))
+
+(define (read-num)
+   (define line (read-line in))
+   (string->number
+       (apply
+            string-append 
+            (string-split
+                (cadr (string-split (string-trim line) ":"))))))
+
+(define time (read-num))
+(define distance (read-num))
+
+(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 (solve time distance))
+(newline)