diff options
| -rw-r--r-- | .gitignore | 4 | ||||
| -rw-r--r-- | 2020/day-05/day-05.rkt | 44 | ||||
| -rw-r--r-- | 2021/day-09/day-09.bak | 60 | ||||
| -rw-r--r-- | 2021/day-10/day-10.rkt | 61 |
4 files changed, 109 insertions, 60 deletions
diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..a9ebf66 --- /dev/null +++ b/.gitignore @@ -0,0 +1,4 @@ +.elixir_ls/* +.cache/* +*.bak +input
\ No newline at end of file diff --git a/2020/day-05/day-05.rkt b/2020/day-05/day-05.rkt new file mode 100644 index 0000000..93c54a2 --- /dev/null +++ b/2020/day-05/day-05.rkt @@ -0,0 +1,44 @@ +#lang racket +(require "../../jj-aoc.rkt" + threading + algorithms) + +(define tickets + (for/list + ([l (in-lines (open-day 5 2020))]) + (~>> l + (regexp-match #px"(.{7})(.{3})" ) + rest))) + +(define (find-place str min-p max-p l r) + (if (string=? "" str) + min-p + (let ([p-range (/ (add1 (- max-p min-p)) 2)] + [c (substring str 0 1)]) + (cond + [(string=? c l) + (find-place (substring str 1) min-p (- max-p p-range) l r)] + [(string=? c r) + (find-place (substring str 1) (+ min-p p-range) max-p l r)])))) + +(define (find-row str) (find-place str 0 127 "F" "B")) +(define (find-col str) (find-place str 0 7 "L" "R")) + +(define (ticket-id t) + (let ([row (find-row (first t))] + [col (find-col (second t))]) + (+ col (* 8 row)))) + +;; part 1 +(define occupied-seats + (~>> (for/list ([t (in-list tickets)]) (ticket-id t)))) + +(apply max occupied-seats) + +;; part 2 +(set-first + (set-subtract (list->set (inclusive-range (apply min occupied-seats) + (apply max occupied-seats))) + (list->set occupied-seats))) + + diff --git a/2021/day-09/day-09.bak b/2021/day-09/day-09.bak deleted file mode 100644 index 11ef8e6..0000000 --- a/2021/day-09/day-09.bak +++ /dev/null @@ -1,60 +0,0 @@ -#lang racket - -(require threading - "../jj-aoc.rkt") - -(define data - (for/vector ([l (in-lines (open-day 9))] - #:unless (equal? l "")) - (~>> l - string->list - (map (λ~>> ~a string->number)) - list->vector))) - -(define max-rows (vector-length data)) -(define max-cols (vector-length (vector-ref data 0))) -(define-values (min-rows min-cols) (values 0 0)) - -(define (vector2d-ref vec coord) - (match-define `(,r ,c) coord) - (~> vec - (vector-ref r) - (vector-ref c))) - -(define (adjacent coords) - (match-define `(,r ,c) coords) - `((,(add1 r) ,c) - (,(sub1 r) ,c) - (,r ,(add1 c)) - (,r ,(sub1 c)))) - -(define (valid-coordinate coord) - (match-define `(,r ,c) coord) - (and (>= r min-rows) - (< r max-rows) - (>= c min-cols) - (< c max-cols))) - -(define (check-adjacent vec coord) - (define x (vector2d-ref vec coord)) - (for*/and ([neighbor (in-list (adjacent coord))] - #:when (valid-coordinate neighbor)) - (x . < . (vector2d-ref vec neighbor)))) - -;; part 1 -(for*/sum ([r (in-range min-rows max-rows)] - [c (in-range min-cols max-cols)] - [x (in-value (vector2d-ref data `(,r ,c)))] - #:when (check-adjacent data `(,r ,c))) - (add1 x)) - -;; part 2 -(define visited (make-hash)) -(define (flood-fill vec coord) - (if (and (< (vector2d-ref vec coord) 9) - (not (hash-has-key? visited coord))) - ((hash-set! visited coord 'visited) - (add1 (for/sum [(neighbor (in-list (adjacent coord))) - #:when (valid-coordinate neighbor)] - (flood-fill vec neighbor)))) - 0))
\ No newline at end of file diff --git a/2021/day-10/day-10.rkt b/2021/day-10/day-10.rkt new file mode 100644 index 0000000..d40d1ea --- /dev/null +++ b/2021/day-10/day-10.rkt @@ -0,0 +1,61 @@ +#lang racket + +(require math/statistics + threading + "../../jj-aoc.rkt") + +(define chunks + (port->lines (open-day 10 2021))) + +(define (opening-bracket? c) + (member c (string->list "([{<"))) + +(define (matching-brackets? c-left c-right) + (member (string c-left c-right) '("()" "[]" "{}" "<>"))) + +(define (parse-brackets lst [acc '()]) + (cond + [(empty? lst) acc] + [(opening-bracket? (first lst)) + (parse-brackets (rest lst) (cons (first lst) acc))] + [(matching-brackets? (first acc) (first lst)) + (parse-brackets (rest lst) (rest acc))] + [else (get-score (first lst))])) + +;; part 1 +(define (get-score c) + (match (string c) + [")" 3] + ["]" 57] + ["}" 1197] + [">" 25137])) + +(define (score-invalid-string chunk) + (match (parse-brackets (string->list chunk)) + [(? list?) 0] + [n n])) + +(for/sum ([chunk (in-list chunks)]) (score-invalid-string chunk)) + +;; part 2 +(define (completion-score lst) + (for/fold ([score 0]) + ([c (in-list lst)]) + (define val + (match (string c) + ["(" 1] + ["[" 2] + ["{" 3] + ["<" 4])) + (+ (* 5 score) val))) + +(define (score-incomplete-string chunk) + (match (parse-brackets (string->list chunk)) + [(? list? lst) (completion-score lst)] + [n 0])) + +(~>> (for*/list ([chunk (in-list chunks)] + [score (in-value (score-incomplete-string chunk))] + #:when (> score 0)) + score) + (median < ))
\ No newline at end of file |