Initial commit

2022/day02/day02.bqn

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+in←|>"AX"⊸-¨0‿2⊸⊏¨•FLines⊑•args
+ShapeScore←{+´1+1⊏˘𝕩}
+WinScore←{+´3×3⊸|1+-˜´˘𝕩}
+•Show (ShapeScore+WinScore)in
+in2←(3⊸|∘⊏˘in+¯1⊸+)⌾(1⊸⊏˘)in
+•Show (ShapeScore+WinScore)in2

2022/day02/day02.rkt

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+#lang racket
+
+(require threading)
+
+(define (read-input filename)
+  (for/list ([l (in-lines (open-input-file filename))])
+    (map string->symbol (string-split l))))
+
+(define (win-score round)
+  (~> (- (cadr round) (car round))
+      (+ 1 _)
+      (modulo _ 3)
+      (* 3 _)))
+
+(define (shape-score round)
+  (+ 1 (cadr round)))
+
+(define (read-play s)
+  (match s
+    ['A 0]
+    ['B 1]
+    ['C 2]
+    ['X 0]
+    ['Y 1]
+    ['Z 2]
+    [_ (error "unrecognized symbol" s)]))
+
+(define (part1 in)
+  (for/sum ([round in])
+    (let ([round (map read-play round)])
+      (+ (shape-score round) (win-score round)))))
+
+(define (choose-play round)
+  (define them (read-play (car round)))
+  (define us
+    (modulo
+     (match (cadr round)
+       ['X (- them 1)]
+       ['Y them]
+       ['Z (+ them 1)]
+       [_ (error "unexpected symbol" (cadr round))])
+     3))
+  (list them us))
+
+(define (part2 in)
+  (for/sum ([round in])
+    (let ([round (choose-play round)])
+      (+ (shape-score round) (win-score round)))))
+
+(define in (read-input "input"))
+(displayln (part1 in))
+(displayln (part2 in))

2022/day02/test

@@ -0,0 +1,3 @@
+A Y
+B X
+C Z