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authorHJ <thechairman@thechairman.info>2021-12-09 18:05:04 -0500
committerHJ <thechairman@thechairman.info>2021-12-09 18:05:04 -0500
commit527bc4762f9c66c9244f0ac1fbee6357478ac9ef (patch)
treeecd3ffc97de5aab201699f93aab1e0417ac3d25d /2020
downloadgleam_aoc-527bc4762f9c66c9244f0ac1fbee6357478ac9ef.tar.gz
gleam_aoc-527bc4762f9c66c9244f0ac1fbee6357478ac9ef.zip
putting all my solutions together in 1 repository
Diffstat (limited to '2020')
-rw-r--r--2020/day-01/day-01.rkt23
-rw-r--r--2020/day-02/day-02.rkt45
-rw-r--r--2020/day-03/day-03.rkt22
3 files changed, 90 insertions, 0 deletions
diff --git a/2020/day-01/day-01.rkt b/2020/day-01/day-01.rkt
new file mode 100644
index 0000000..56c0b87
--- /dev/null
+++ b/2020/day-01/day-01.rkt
@@ -0,0 +1,23 @@
+#lang racket
+(require "../../jj-aoc.rkt"
+ threading)
+
+(define entries
+ (~>> (open-day 01 2020)
+ (port->list read)
+ list->set))
+
+;; part 1
+(define (look-for-complement xs)
+ (define x (set-first xs))
+ (cond
+ [(set-member? xs (- 2020 x)) (* x (- 2020 x))]
+ [else (look-for-complement (set-rest xs))]))
+
+(time (look-for-complement entries))
+
+;; part 2
+(time (for*/first ([x (in-set entries)]
+ [y (in-set (set-subtract entries (set x)))]
+ #:when (set-member? (set-subtract entries (set x y)) (- 2020 x y)))
+ (* x y (- 2020 x y)))) \ No newline at end of file
diff --git a/2020/day-02/day-02.rkt b/2020/day-02/day-02.rkt
new file mode 100644
index 0000000..3296d32
--- /dev/null
+++ b/2020/day-02/day-02.rkt
@@ -0,0 +1,45 @@
+#lang racket
+(require "../../jj-aoc.rkt"
+ threading)
+
+(struct policy (least most char pwd) #:transparent)
+
+(define (make-policy least-str most-str char-str pwd)
+ (policy (string->number least-str)
+ (string->number most-str)
+ (string-ref char-str 0)
+ pwd))
+
+(define policies
+ (for/list ([l (in-lines (open-day 02 2020))])
+ (~>> l
+ (regexp-match #px"(\\d+)-(\\d+) (\\w): (.*)")
+ rest
+ (apply make-policy))))
+
+;; part 1
+(define (valid-policy? p)
+ (~>> p
+ policy-pwd
+ string->list
+ (count (curry char=? (policy-char p)))
+ ((λ (n) (and (>= n (policy-least p))
+ (<= n (policy-most p)))))))
+
+(for/sum ([p (in-list policies)]
+ #:when (valid-policy? p))
+ 1)
+
+;; part 2
+(define (valid-revised-policy? p)
+ (~>> p
+ policy-pwd
+ string->list
+ ((λ (lst) (list (list-ref lst (sub1 (policy-most p)))
+ (list-ref lst (sub1 (policy-least p))))))
+ (count (curry char=? (policy-char p)))
+ (= 1)))
+
+(for/sum ([p (in-list policies)]
+ #:when (valid-revised-policy? p))
+ 1) \ No newline at end of file
diff --git a/2020/day-03/day-03.rkt b/2020/day-03/day-03.rkt
new file mode 100644
index 0000000..f540ee6
--- /dev/null
+++ b/2020/day-03/day-03.rkt
@@ -0,0 +1,22 @@
+#lang racket
+(require "../../jj-aoc.rkt"
+ threading)
+
+(define (check-for-trees run rise)
+ (for*/sum ([(row i) (in-indexed (port->lines (open-day 3 2020)))]
+ #:when (= 0 (modulo i rise))
+ [possible-tree (in-value (sequence-ref (in-cycle row) (* (/ run rise) i)))]
+ #:when (and (char=? possible-tree #\#)))
+ 1))
+
+;; part 1
+(check-for-trees 3 1)
+
+;; part 2
+(~>> '((1 1)
+ (3 1)
+ (5 1)
+ (7 1)
+ (1 2))
+ (map (curry apply check-for-trees))
+ (apply *)) \ No newline at end of file