Solve day05

2 files changed, 72 insertions, 5 deletions

diff --git a/src/aoc_2022/day05.clj b/src/aoc_2022/day05.clj
index fcfda0b..9b07a16 100644
--- a/src/aoc_2022/day05.clj
+++ b/src/aoc_2022/day05.clj
@@ -1,10 +1,74 @@
 (ns aoc-2022.day05)
 (require '[aoc-2022.utils :refer :all])
 
-(def task1
-  (chain))
+(defn split-by-empty-line [rows]
+  (split-by "" rows))
 
-(def task2
-  (chain))
+(defn revv [v] (vec (rseq v)))
 
-(run-aoc "day05" task1 task2)
+(defn parse-stacks [stacks]
+  (->> stacks
+       transpose
+       (keep-indexed #(if (zero? (mod (- %1 1) 4)) %2 nil))
+       (map #(filter (partial not= \ ) %))
+       (map #(drop-last %))
+       (map vec)))
+
+(defn parse-instrs [instrs]
+  (->> instrs
+       (map #(split-by \  %))
+       (map (partial keep-indexed #(if (odd? %1) (apply str %2) nil)))
+       (map (partial map to-long))
+       (map vec)
+       ))
+
+(defn prepare [rows]
+  (let [[stack-rows instr-rows] (split-by-empty-line rows)
+        stacks (parse-stacks stack-rows)
+        instrs (parse-instrs instr-rows)]
+    (list (vec stacks) (vec instrs))))
+
+(defn run-instr1 [[n from to] stacks]
+  (if (zero? n)
+    stacks
+    (let [from-stack (stacks (dec from))
+          to-stack (stacks (dec to))
+          val (first from-stack)
+          new-from-stack (vec (rest from-stack))
+          new-to-stack (vec (cons val to-stack))
+          new-stacks' (assoc stacks (dec from) new-from-stack)
+          new-stacks (assoc new-stacks' (dec to) new-to-stack)]
+      (run-instr1 [(dec n) from to] new-stacks))))
+
+(defn run-instrs1 [[instr & is] stacks]
+  (if (seq instr)
+    (run-instrs1 (vec is) (run-instr1 instr stacks))
+    stacks))
+
+(defn task1 [rows]
+  (let [[stacks instrs] (prepare rows)]
+    (->> (run-instrs1 instrs stacks)
+         (map first)
+         (apply str))))
+
+(defn run-instr2 [[n from to] stacks]
+  (let [from-stack (stacks (dec from))
+        to-stack (stacks (dec to))
+        vals (vec (take n from-stack))
+        new-from-stack (vec (drop n from-stack))
+        new-to-stack (vec (concat vals to-stack))
+        new-stacks' (assoc stacks (dec from) new-from-stack)]
+    (assoc new-stacks' (dec to) new-to-stack)))
+
+(defn run-instrs2 [[instr & is] stacks]
+  (if (seq instr)
+    (run-instrs2 (vec is) (run-instr2 instr stacks))
+    stacks))
+
+(defn task2 [rows]
+  (let [[stacks instrs] (prepare rows)]
+    (->> (run-instrs2 instrs stacks)
+         (map first)
+         (apply str))))
+
+(run-aoc "day05" task1 task2)
\ No newline at end of file
diff --git a/src/aoc_2022/utils.clj b/src/aoc_2022/utils.clj
index c59d498..cfa9530 100644
--- a/src/aoc_2022/utils.clj
+++ b/src/aoc_2022/utils.clj
@@ -21,6 +21,9 @@
 
 (def split-by #(split-by' %1 '() %2))
 
+(defn transpose [m]
+  (apply mapv vector m))
+
 ; Advent of Code specific
 
 (defn read-aoc [day]