From dcc3c287bb8cd463720e4bc401662217a45b6ca1 Mon Sep 17 00:00:00 2001
From: Samuel Ortion <samuel@ortion.fr>
Date: Sun, 2 Jun 2024 20:05:55 +0200
Subject: [PATCH] Solve part 2 of Not Quite Lisp

---
 2015/days/01/lisp.lisp  |  3 +++
 2015/days/01/lisp2.lisp | 27 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 2015/days/01/lisp2.lisp

diff --git a/2015/days/01/lisp.lisp b/2015/days/01/lisp.lisp
index 9e7fe98..fa4889c 100644
--- a/2015/days/01/lisp.lisp
+++ b/2015/days/01/lisp.lisp
@@ -1,4 +1,7 @@
 ;; Day 1: Not Quite Lisp
+;;
+;; Part 1: What is the floor Santa takes ?
+
 
 (defparameter balance 0)
 
diff --git a/2015/days/01/lisp2.lisp b/2015/days/01/lisp2.lisp
new file mode 100644
index 0000000..938432d
--- /dev/null
+++ b/2015/days/01/lisp2.lisp
@@ -0,0 +1,27 @@
+;; Day 1: Not Quite Lisp
+;;
+;; Part 2: Position of the character with balance -1 (basement)
+;;
+;; ref.
+;; - read: https://lispcookbook.github.io/cl-cookbook/files.html
+
+(defparameter balance 0)
+(defparameter position 0)
+
+(defun direction (char) (cond
+                           ((char= char #\()
+                            +1)
+                           ((char= char #\))
+                            -1)
+                        ))
+
+(with-open-file (in "./data/input")
+  (loop for char = (read-char in nil)
+        until (= balance -1)
+        do
+       (setf balance
+             (+ balance (direction char)))
+       (setf position
+             (+ position 1))))
+
+(print position)