X-Git-Url: http://git.jkinsey.net/?p=adventofcode2020.git;a=blobdiff_plain;f=src%2Futilities.lisp;h=ce9aa6d39ce67b27c0608dda35c3adf23e5e18b9;hp=ab6c3e8faa36eb6d59ac780c1ae7d8f6670a142b;hb=HEAD;hpb=63a814f25cb8eff79f8f566f75b7b5fdac549f5f

diff --git a/src/utilities.lisp b/src/utilities.lisp
index ab6c3e8..ce9aa6d 100644
--- a/src/utilities.lisp
+++ b/src/utilities.lisp
@@ -6,7 +6,10 @@
   (split "\\n" str))
 
 (defun int-list-from (str)
-  (mapcar #'parse-integer (split "\\n" str)))
+  (mapcar #'parse-integer (list-from str)))
+
+(defun list-list-from (str)
+  (split-sequence "" (list-from str) :test #'string=))
 
 (defun cartesian-product (A B &rest C)
   (let ((helper (lambda (X Y)
@@ -17,6 +20,11 @@
         (wrap-A (mapcar #'list A)))
     (reduce helper C :initial-value (funcall helper wrap-A B))))
 
+(defun manhattan-distance (a b)
+  (destructuring-bind ((ax ay) (bx by)) (list a b)
+    (+ (abs (- ax bx))
+       (abs (- ay by)))))
+
 (def-suite util)
 (in-suite util)