Day 6

aoc20.lisp

@@ -212,3 +212,22 @@
     (time (progn (print (solve-5-1 (copy-seq data)))
 		 (solve-5-2 data)
 		 (print p1-answer)))))
+
+(defun read-forms (stream)
+  (loop for line = (read-line stream nil)
+	while (and line (not (string= line "")))
+	collect line))
+
+(defun read-6 (file)
+  (with-open-file (stream file)
+    (loop while (peek-char nil stream nil)
+	  collect (read-forms stream))))
+
+(defun solve-6-1 (data)
+  (reduce (lambda (x y) (+  (if (consp x) (length x) x) (length y)))
+	  (map 'list (lambda (form) (remove-duplicates (apply #'concatenate 'list form))) data)))
+
+(defun solve-6-2 (data)
+  (length (mapcan (lambda (entry)
+		    (reduce #'intersection (map 'list (lambda (l) (coerce l 'list)) entry)))
+		  data)))