[p7] done both parts

but i want to try a different approach

p7/p7.org

@@ -0,0 +1,61 @@
+#+title: Solution to p7
+
+Yay, another 2D problem
+#+begin_src emacs-lisp :results none
+  (with-temp-buffer
+    (insert-file-contents "input")
+    (advent/replace-multiple-regex-buffer
+     '(("^\\(.*\\)$" . "\"\\1\" ")))
+    (goto-char (point-min))
+    (insert "(setq data '(")
+    (goto-char (point-max))
+    (insert "))")
+    (eval-buffer))
+
+  (setq data-char (-map #'advent/split-string-into-char-list data)
+        width (length (car data-char))
+        height (length data-char))
+#+end_src
+
+This is for part 1; 
+#+begin_src emacs-lisp
+
+
+    (defun position-valid-p (pos)
+      (and (and (>= (car pos) 0) (< (car pos) width))
+           (and (>= (cadr pos) 0) (< (cadr pos) height))))
+
+  (advent/char-at '(-1 0) data-char)
+
+  (defun tachyon-step (el)
+    (if (not (position-valid-p el)) (list el)
+      (let ((down (advent/neighbour el '(0 1))))
+        (if (or (not (position-valid-p down))
+  	      (not (eq ?^ (advent/char-at down data-char))))
+  	  (list down)
+  	(push down splits)
+  	(--map (advent/neighbour el it) '((-1 0) (1 0)))))))
+  (setq tachyons (advent/coordinates-of ?S data-char))
+  (setq splits nil)
+  (length (--fix (-distinct (-mapcat 'tachyon-step it)) tachyons))
+  (length (-distinct splits))
+#+end_src
+
+#+RESULTS:
+: 1507
+
+#+begin_src emacs-lisp
+  (defun tachyon-step-freq (el)
+      (--map (cons it (cdr el)) (tachyon-step (car el))))
+
+  (setq tachyons (cons (car (advent/coordinates-of ?S data-char)) 1))
+
+  (defun compress (li)
+    (--map (cons it (-sum (-map #'cdr (-filter (lambda (x) (equal it (car x))) li)))) (-distinct (-map #'car li))))
+
+  (-sum (-map #'cdr (--fix (compress (-mapcat 'tachyon-step-freq it)) (list tachyons))))
+
+#+end_src
+
+#+RESULTS:
+: 1537373473728