add days 1 and 2

README.md

@@ -1,9 +1,9 @@
 # Advent of Code 2021
 
-| Day | Chicken Scheme | Scala  | Python | Nim |
-|-----|----------------|--------|--------|-----|
-| 1   | ✅ (to commit) |        |        |     |
-| 2   | ✅ (to commit) |        |        |     |
+| Day | CHICKEN | Scala  | Python | Nim |
+|-----|---------|--------|--------|-----|
+| 1   | ✅      |        |        |     |
+| 2   | ✅      |        |        |     |
 | 3   | part 1  | part 1 | ✅     |     |
 | 4   |         |        | ✅     |     |
 | 5   |         |        | ✅     |     |

day01.scm

@@ -0,0 +1,30 @@
+(import (chicken io))
+(import (chicken format))
+(import srfi-1)
+
+(define (parse inputs)
+    (let ((line (read-line)))
+        (if (not (eof-object? line))
+            (parse (cons (string->number line) inputs))
+            inputs)))
+
+(define (inc-if cond num)
+    (if cond (+ num 1) num))
+
+(define (part1 inputs previous counter)
+    (if (not (null? inputs)) 
+        (let ((head (car inputs)))
+            (part1 (cdr inputs) head (inc-if (<= head previous) counter)))
+        counter))
+
+
+(define (part2 inputs previous counter)
+    (if (not (eq? inputs '()))
+        (let ((sum (apply + (take-right! inputs 3))))
+            (part2 (cdr inputs) sum (inc-if (<= sum previous) counter)))
+        counter))
+
+(let ((inputs (parse '())))
+    (format #t "inputs = ~A~%" inputs)
+    (format #t "part1 = ~A~%" (part1 inputs 0 0))
+    (format #t "part2 = ~A~%" (part2 inputs 0 0)))

day02.scm

@@ -0,0 +1,48 @@
+(import (chicken io))
+(import (chicken format))
+(import (chicken string))
+(import (chicken condition))
+(import srfi-1)
+
+(define (parse-line line)
+    (let-values (((command offset) (apply values (string-split line))))
+        (list command (string->number offset))))
+
+(define (parse inputs)
+    (map parse-line (read-lines)))
+
+(define (part1-direction head tail h d)
+    (let-values (((command offset) (apply values head)))
+        (cond ((equal? command "forward") 
+               (part1 tail (+ h offset) d))
+              ((equal? command "down")
+               (part1 tail h (+ d offset)))
+              ((equal? command "up")
+               (part1 tail h (- d offset)))
+              (else (abort (format "did not expect command '~A'" command))))))
+
+(define (part1 directions h d)
+    (if (not (null? directions))
+        (part1-direction (car directions) (cdr directions) h d)
+        (* h d)))
+
+
+(define (part2-direction head tail horiz depth aim)
+    (let-values (((command offset) (apply values head))) 
+        (cond ((equal? (car command) "forward") 
+               (part2 tail (+ horiz offset) (+ depth (* aim offset)) aim))
+              ((equal? command "down")
+               (part2 tail horiz depth (+ aim offset)))
+              ((equal? command "up")
+               (part2 tail horiz depth (- aim offset)))
+              (else (abort (format "did not expect command '~A'" command))))))
+
+(define (part2 directions horiz depth aim)
+    (if (not (null? directions))
+        (part2-direction (car directions) (cdr directions) horiz depth aim)
+        (* horiz depth)))
+    
+
+(let ((directions (parse '())))
+    (format #t "part1 = ~A~%" (part1 directions 0 0))
+    (format #t "part2 = ~A~%" (part2 directions 0 0 0)))