Add cl-interpol

[adventofcode2020.git] / src / utilities.lisp

diff --git a/src/utilities.lisp b/src/utilities.lisp
index 91e74d11b1aeb5a8a6316c11562e7934f9eb0aa1..ce9aa6d39ce67b27c0608dda35c3adf23e5e18b9 100644 (file)
--- a/src/utilities.lisp
+++ b/src/utilities.lisp
@@ -8,6 +8,9 @@
 (defun int-list-from (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)
                   (if Y (loop for x in X
@@ -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)