Advent of (shit)Code
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;;;; AoC 2020
;;; Day 1
(defun read-1 (file)
(with-open-file (stream file)
(loop for line = (read-line stream nil)
while line
collect (parse-integer line))))
(defvar *input-1-0* nil)
(setf *input-1-0* (read-1 "inputs/1-0"))
(defvar *input-1-1* nil)
(setf *input-1-1* (read-1 "inputs/1-1.txt"))
(defun solve-1-1 (data target)
(let ((deficits (map 'list (lambda (n) (- target n)) data)))
(reduce #'* (intersection data deficits))))
(defun make-deficits (list difference)
(map 'list (lambda (n) (- difference n)) list))
(defun solve-1-2 (data target)
(let ((first-deficits (make-deficits data target)))
(reduce #'*
(remove-duplicates
(mapcan (lambda (n)
(intersection (make-deficits data n) data))
first-deficits)))))
(defun solve-1 (data target)
(time (progn
(print (solve-1-1 data target))
(print (solve-1-2 data target)))))
;;; Day 2
(defstruct password
(pchar)
(prange)
(word))
(defun read-2 (file)
(with-open-file (stream file)
(loop for line = (read-line stream nil)
while line
collect (let* ((pwlist (split-sequence:split-sequence #\space line))
(range (multiple-value-bind (n index)
(parse-integer (first pwlist) :junk-allowed t)
(list n (parse-integer (first pwlist) :start (1+ index))))))
(make-password
:pchar (char (second pwlist) 0)
:prange range
:word (third pwlist))))))
(defun %solve-2-1 (pw)
(let ((n (count (password-pchar pw) (password-word pw))))
(and (not (> (first (password-prange pw)) n))
(not (< (second (password-prange pw)) n)))))
(defun %solve-2-2 (pw)
(let ((valid 0))
(loop for index in (password-prange pw)
do (if (eq (password-pchar pw) (elt (password-word pw) (1- index)))
(incf valid)))
(= valid 1)))
(defun %solve-2 (data test)
(let ((pn 0))
(loop for p in data
do (if (funcall test p)
(incf pn)))
pn))
(defun solve-2 (file)
(let ((data (read-2 file)))
(time (progn (print (%solve-2 data #'%solve-2-1))
(print (%solve-2 data #'%solve-2-2))))))
;;; Day 3
(defun read-3 (file)
(with-open-file (stream file)
(let ((temp-map (loop for line = (read-line stream nil)
while line
collect line)))
(make-array (list (length temp-map) (length (first temp-map)))
:initial-contents temp-map
:element-type 'character))))
(defun step-slope (position direction map)
(let* ((temp-position (map 'list #'+ direction position))
(overflow (map 'list #'> temp-position (array-dimensions map))))
(cond ((first overflow) :bottom)
((second overflow)
(progn (decf (second temp-position) (second (array-dimensions map)))
temp-position))
(t temp-position))))
(defun solve-3-1 (direction map)
(let ((tree-count 0))
(labels ((rec (position)
(let ((zero-pos (map 'list #'1- position))
(new-pos (step-slope position direction map)))
(if (char= (aref map (first zero-pos) (second zero-pos))
#\#)
(incf tree-count))
(unless (eq new-pos :bottom)
(rec new-pos)))))
(rec '(1 1))
tree-count)))
;; (height width)
(defun solve-3-2 (slopes map)
(reduce #'* (loop for slope in slopes
collecting (solve-3-1 slope map))))
(defun solve-3 (map)
(time (let ((data (read-3 map)))
(print (solve-3-1 '(1 3) data))
(print (solve-3-2 '((1 1) (1 3) (1 5) (1 7) (2 1)) data)))))
;;; Day 4
(defvar *passport-fields* (list "byr" "iyr" "eyr" "hgt" "hcl" "ecl" "pid" "cid"))
(defvar *passport-rules-broken* (list nil nil nil nil nil nil nil (lambda (n) (declare (ignore n)) t)))
(defvar *passport-rules* nil)
(setf *passport-rules*
(list (lambda (n) (and n (let ((nn (ignore-errors (parse-integer n))))
(and nn (>= nn 1920) (<= nn 2002)))))
(lambda (n) (and n (let ((nn (ignore-errors (parse-integer n))))
(and nn (>= nn 2010) (<= nn 2020)))))
(lambda (n) (and n (let ((nn (ignore-errors (parse-integer n))))
(and nn (>= nn 2020) (<= nn 2030)))))
(lambda (h) (and h (multiple-value-bind (n offset) (parse-integer h :junk-allowed t)
(let ((unit (subseq h offset)))
(cond ((string= unit "cm")
(and (>= n 150) (<= n 193)))
((string= unit "in")
(and (>= n 59) (<= n 76))))))))
(lambda (c) (and c
(= (length c) 7)
(char= (elt c 0) #\#)
(parse-integer (subseq c 1) :radix 16)))
(lambda (c) (and c (member c '("amb" "blu" "brn" "gry" "grn" "hzl" "oth") :test #'equal)))
(lambda (pid) (and pid
(= 9
(length pid)
(length (remove-if (lambda (n) (not (digit-char-p n))) pid)))))
(lambda (cid) (declare (ignore cid)) t)))
(defun read-passport (stream)
(let ((passport-list
(apply #'concatenate 'list
(loop for line = (read-line stream nil)
while (and line (not (string= line "")))
collect (split-sequence:split-sequence #\space line))))
(current-passport (make-hash-table :test 'equal)))
(loop for key in passport-list
do (setf (gethash (subseq key 0 3) current-passport)
(subseq key 4)))
current-passport))
(defun read-4 (file)
(with-open-file (stream file)
(loop while (peek-char nil stream nil)
collect (read-passport stream))))
(defun %solve-4 (data tests)
(let ((valid-count 0))
(loop for passport in data
do (unless (member 'nil
(map 'list (lambda (field test)
(if test
(funcall test (gethash field passport))
(gethash field passport)))
*passport-fields* tests))
(incf valid-count)))
valid-count))
(defun solve-4 (file)
(let ((data (read-4 file)))
(time (progn (print (%solve-4 data *passport-rules-broken*))
(print (%solve-4 data *passport-rules*))))))
(defun binarize (string bits)
(parse-integer (substitute
#\1 (elt bits 1)
(substitute
#\0 (elt bits 0) string))
:radix 2))
;;; Day 5
(defun read-5 (file)
(with-open-file (stream file)
(loop for line = (read-line stream nil)
while line
collect (map 'list #'binarize (list (subseq line 0 7) (subseq line 7)) '("FB" "LR")))))
(defun boarding-ids (data)
(map 'list (lambda (seat) (+ (* 8 (first seat)) (second seat))) data))
(defun solve-5-1 (data)
(first (sort (boarding-ids data) #'>)))
(defvar p1-answer)
(defun report-significant-difference (x y)
(if (not (= (- x y) 1))
(setf p1-answer (1- x)))
y)
(defun solve-5-2 (data)
(reduce #'report-significant-difference (sort (boarding-ids data) #'>)))
(defun solve-5 (file)
(declare (special p1-answer)) (let ((data (read-5 file))
(p1-answer nil))
(time (progn (print (solve-5-1 (copy-seq data)))
(solve-5-2 data)
(print p1-answer)))))
;;; Day 6
(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)))
(defun solve-6 (file)
(let ((data (read-6 file)))
(time (progn (print (solve-6-1 data))
(print (solve-6-2 data))))))
;;; day 7
(defun read-bag (line)
(let ((key-bound (search "bags" line)))
(list (subseq line 0 (1- key-bound))
(map 'list (lambda (r)
(multiple-value-bind (n index) (parse-integer r :junk-allowed t)
(unless (search "no other" r)
(list (subseq r (1+ index) (1- (search "bag" r))) n))))
(split-sequence:split-sequence
#\, (subseq line (+ 1 (length "bags contain") key-bound)))))))
(defun read-7 (file)
(with-open-file (stream file)
(loop for line = (read-line stream nil)
while line
collect (read-bag line))))
(defun build-graph (data)
(map 'list (lambda (entry)
(set (intern (first entry))
(if (null (first (second entry)))
nil
(map 'list (lambda (r) (cons (intern (first r)) (second r)))
(second entry)))))
(copy-seq data)))
(defun recursive-search (node symbol)
(cond ((eq node nil) nil)
((member symbol (map 'list #'car node)) t)
(t (or (recursive-search (eval (caar node)) symbol)
(recursive-search (cdr node) symbol)))))
(defun solve-7-1 (data target)
(length (remove-if #'null
(map 'list (lambda (sym)
(recursive-search (eval sym) target))
(map 'list (lambda (entry) (intern (first entry))) data)))))
(defun count-bags (node &optional cheat)
(let* ((node (if (symbolp node) (eval node) node))
(bag-multiplier-up (or (cdar node) 0))
(bags-up (caar node))
(bags-right (cdr node)))
(cond (cheat 1)
((null node) 0)
((not (null (eval (caar node))))
(+ (* bag-multiplier-up (count-bags bags-up))
(count-bags bags-right)
bag-multiplier-up))
(t (+ (* bag-multiplier-up (count-bags bags-up (if (null (eval bags-up)) t)))
(count-bags bags-right))))))
(defun solve-7-2 (node)
(1- (count-bags (list (cons node 1)))))
(defun solve-7 (file target-bag)
(let ((data (read-7 file))
(symbol (intern target-bag)))
(time (progn (build-graph data)
(print (solve-7-1 data symbol))
(print (solve-7-2 symbol))))))
;;; day 8
;;; intcode again
(defun read-8 (file)
(let ((data (with-open-file (stream file)
(loop for line = (read-line stream nil)
while line
collect (let ((seq (split-sequence:split-sequence #\space line)))
(list (first seq) (parse-integer (second seq))))))))
(make-array (length data) :initial-contents data)))
(defun %solve-8 (data &optional alter)
(let* ((accumulator 0)
(position 0)
(ht (make-hash-table))
(lambdas (list (cons "nop" (lambda (n) (declare (ignore n)) (incf position)))
(cons "acc" (lambda (n) (incf position) (incf accumulator n)))
(cons "jmp" (lambda (n) (incf position n))))))
(labels ((rec (fiddle-ins)
(cond ((gethash position ht)
(unless alter accumulator))
((>= position (length data))
(values accumulator "EOF"))
(t (progn (setf (gethash position ht) (first (aref data position)))
(funcall (cdr (assoc
(or (if (eql position fiddle-ins)
(if (string= (first (aref data position))
"nop")
"jmp" "nop")
nil)
(first (aref data position)))
lambdas :test #'equal))
(second (aref data position)))
(rec fiddle-ins))))))
(let ((p1 (rec nil))
(index-list nil))
(if alter
(progn
(maphash (lambda (k v) (if (or (string= v "nop") (string= v "jmp"))
(push k index-list)))
ht)
(first (remove-if #'null (map 'list (lambda (n)
(setf accumulator 0
position 0
ht (make-hash-table))
(rec n))
index-list))))
p1)))))
(defun solve-8 (file)
(let ((data (read-8 file)))
(time (progn (print (%solve-8 data))
(print (%solve-8 data t))))))
;;; Day 9
(defun read-9 (file)
(apply #'vector
(with-open-file (stream file)
(loop for line = (read-line stream nil)
while line
collect (parse-integer line)))))
(defun step-xmas (seed-size data &optional (index 0))
(let* ((target (aref data (+ seed-size index)))
(window-list (coerce (subseq data index (+ index seed-size)) 'list))
(deficits (map 'list (lambda (n) (- target n)) window-list))
(pairs (intersection deficits window-list)))
;; (format t "~a, ~a, ~a ~%" target window-list deficits)
(if (< 1 (length pairs))
pairs target)))
(defun walk-xmas (seed-size data)
(loop for index from 0 to (- (length data) 1 seed-size)
collecting (step-xmas seed-size data index)))
(defun solve-9-1 (seed-size data)
(first (remove-if #'consp (walk-xmas seed-size data))))
(defun caterpillar (data target tail head)
(let ((range-sum (reduce #'+ (subseq data tail head))))
(cond ((> target range-sum)
(caterpillar data target tail (1+ head)))
((< target range-sum)
(caterpillar data target (1+ tail) head))
(t (subseq data tail head)))))
(defun solve-9-2 (data target)
(let ((range (sort (caterpillar data target 0 1) #'>)))
(+ (aref range 0) (aref range (1- (length range))))))
(defun solve-9 (file &optional (step-size 25))
(time (let* ((data (read-9 file))
(p1 (solve-9-1 step-size data)))
(print p1)
(print (solve-9-2 data p1)))))
;;; Day 10
(defun read-10 (file)
(read-9 file))
(defun solve-10-1 (data)
(let ((data (sort data #'<))
(steps (list 1 0 1)))
(reduce (lambda (x y)
(let ((difference (- y x)))
(incf (nth (1- difference) steps))
y))
data)
(* (first steps) (third steps))))
(let ((ht (make-hash-table)))
(defun recurse-adapters (data)
(if (gethash (car data) ht)
(gethash (car data) ht)
(setf (gethash (car data) ht)
(%recurse-adapters data)))))
(defun %recurse-adapters (data)
(if (null (cdr data))
1
(let ((ceiling (+ 3 (first data))))
(reduce #'+ (map 'list #'recurse-adapters
(remove-if-not
#'consp
(list (and (cdr data) (>= ceiling (cadr data)) (cdr data))
(and (cddr data) (>= ceiling (caddr data)) (cddr data))
(and (cdddr data) (>= ceiling (cadddr data)) (cdddr data)))))))))
(defun solve-10-2 (data)
(let* ((data (cons 0 (coerce (sort data #'<) 'list))))
(recurse-adapters data)))
(defun solve-10 (file)
(let ((data (read-10 file)))
(time (progn (print (solve-10-1 data))
(print (solve-10-2 data))))))