Merge branch 'master' of git.ajet.fyi:ajet/advent-of-code

.gitignore

@@ -17,3 +17,6 @@ target/
 .cpcache
 .calva
 .nrepl-port
+
+## intellij nonsense
+.idea

2017/.gitignore

@@ -0,0 +1,4 @@
+input/
+.lein-repl-history
+.idea/
+*.iml

2017/project.clj

@@ -0,0 +1,15 @@
+(defproject org.ajet/advent-of-code "0.0.0-SNAPSHOT"
+  :description "my 2017 advent of code solutions in clojure"
+  :url "http://github.com/ajetski/advent-of-code"
+  :min-lein-version "2.0.0"
+  :jvm-opts ["-Xmx16g"]
+  :plugins [[cider/cider-nrepl "0.57.0"]]
+  :dependencies [[org.clojure/clojure "1.12.0"]
+                 [org.clojure/data.priority-map "1.2.0"]
+                 [org.clojure/math.combinatorics "0.3.0"]
+                 [babashka/fs "0.5.23"]
+                 [org.babashka/http-client "0.4.22"]
+                 [org.clojure/core.match "1.1.0"]
+                 [clj-python/libpython-clj "2.025"]
+                 [tools.aqua/z3-turnkey "4.14.1"]]
+ :source-paths ["src" "../shared/clj/src"])

2017/src/day01.clj

@@ -0,0 +1,23 @@
+(ns day01
+  (:require input-manager))
+
+(defn to-digit [c] (Character/digit c 10))
+
+(def input (mapv to-digit (input-manager/get-input-raw 2017 01)))
+
+(defn solve [offset]
+  (let [lookup (fn [idx]
+                 (input (mod idx (count input))))]
+      (->> input
+              (map-indexed vector)
+              (filter (fn [[idx el]]
+                        (= el (lookup (+ offset idx)))))
+              (map second)
+              (apply +))))
+
+;; part 1
+(solve 1)
+
+;; part 2
+(solve (/ (count input) 2))
+

2017/src/day02.clj

@@ -0,0 +1,25 @@
+(ns day02
+  (:require input-manager
+            core))
+
+(def input (mapv (comp #(mapv parse-long %)
+                       core/split-whitespace)
+                 (input-manager/get-input 2017 02)))
+
+;; part 1
+(->> input
+     (map (comp #(apply - %)
+                (juxt #(apply max %)
+                      #(apply min %))))
+     (apply +))
+
+(defn find-divisible [l]
+  (or (first
+       (for [a (range (count l))
+             b (range (count l))
+             :when (and (not= a b)
+                        (= (mod (l a) (l b)) 0))]
+         (/ (l a) (l b))))
+      0))
+
+(apply + (map find-divisible input))

2017/src/day04.clj

@@ -0,0 +1,18 @@
+(ns day04
+  (:require input-manager
+            core))
+
+(def input (map core/split-whitespace (input-manager/get-input 2017 04)))
+
+;; part 1
+(->> input
+     (filter #(= (count %)
+                 (count (into #{} %))))
+     count)
+
+;; part 2
+(->> input
+     (filter #(= (count (into #{} (map frequencies %)))
+                 (count %)))
+     count)
+

2017/src/day05.clj

@@ -0,0 +1,30 @@
+(ns day05
+  (:require input-manager))
+
+(def input (->> (input-manager/get-input 2017 5)
+                (mapv parse-long)))
+
+(def MAX_IDX (count input))
+
+;; part 1
+(loop [steps 0
+       maze input
+       idx 0]
+  (let [maze' (update maze idx inc)
+        idx' (+ (maze idx) idx)]
+    (if (< -1 idx' MAX_IDX)
+      (recur (inc steps) maze' idx')
+      (inc steps))))
+
+;; part 2
+(loop [steps 0
+       maze input
+       idx 0]
+  (let [offset (maze idx)
+        maze' (update maze idx (if (>= offset 3)
+                                 dec
+                                 inc))
+        idx'  (+ offset idx)]
+    (if (< -1 idx' MAX_IDX)
+      (recur (inc steps) maze' idx')
+      (inc steps))))

2017/src/day06.clj

@@ -0,0 +1,26 @@
+(ns day06
+  (:require [input-manager]
+            [core :refer [split-whitespace]]))
+
+(def input
+  (->> (input-manager/get-input-raw 2017 6)
+       split-whitespace
+       (mapv parse-long)))
+
+(loop [state input
+       i 0
+       seen {}]
+  (if  (contains? seen state)
+    {:part-one i
+     :part-two (- i (seen state))}
+    (let [cnt  (apply max state)
+          idx (->> state
+                   (map-indexed vector)
+                   (filter #(= (second %) cnt))
+                   ffirst)]
+      (recur (->> (range cnt)
+                  (map #(mod (+ idx 1 %) (count state)))
+                  (reduce #(update %1 %2 inc) (assoc state idx 0)))
+             (inc i)
+             (assoc seen state i)))))
+

2017/src/day07.clj

@@ -0,0 +1,67 @@
+(ns day07
+  (:require
+   [clojure.string :as str]
+   [core :refer [split-whitespace]]
+   [input-manager]))
+
+(def input
+  (->> (input-manager/get-input-raw 2017 7)
+       str/split-lines
+       (map (comp split-whitespace
+                  #(str/replace % #"," "")))))
+
+;; part 1
+(def base-node
+  (->> input
+       (filter (fn [[_ _ _ & children]] children))
+       (filter (fn [[node]]
+                 (empty? (filter (fn [[_ _ _ & children]]
+                                   (some #(= % node) children))
+                                 input))))
+       ffirst))
+
+(do
+  (def get-depth
+    (memoize (fn [node]
+               (let [[_ w-str _ & children] (first (filter (fn [[n]] (= node n))
+                                                           input))
+                     w (parse-long (subs w-str 1 (dec (count w-str))))]
+                 (apply + w (map get-depth children))))))
+  (def get-weight
+    (memoize (fn [node]
+               (let [w-str (->> input
+                                (filter (fn [[n]] (= node n)))
+                                first
+                                second)]
+                 (parse-long (subs w-str 1 (dec (count w-str))))))))
+  (def get-children
+    (memoize (fn [node] (->> input
+                             (filter (fn [[n]] (= node n)))
+                             first
+                             (drop 3))))))
+
+(defn get-children-data [node]
+  (map (juxt identity get-depth get-weight) (get-children node)))
+
+(defn get-counts [data]
+  (->> data
+         (map second)
+         frequencies
+         (sort-by second)))
+
+;; part 2
+(let [[bad-parent bad-node]
+      (loop [parent nil
+             node base-node]
+        (let [data (get-children-data node)
+              counts (get-counts data)
+              row (first (filter #(= (second %) (ffirst counts)) data))]
+          (if (= (count counts) 1)
+            [parent node]
+            (recur node (first row)))))
+      diff (->> bad-parent
+                get-children-data
+                get-counts
+                (map first)
+                (apply -))]
+  (- (get-weight bad-node) diff))

2017/src/day08.clj

@@ -0,0 +1,46 @@
+(ns day08
+  (:require
+   [clojure.string :as str]
+   [core]
+   [input-manager]))
+
+(def op {"inc" +
+         "dec" -})
+(def cond-op {"<" <
+              "<=" <=
+              ">" >
+              ">=" >=
+              "==" =
+              "!=" not=})
+(def input (map (comp
+                 (fn [[name operation num _ cond-name cond-operation cond-val]]
+                   [name
+                    (op operation)
+                    (parse-long num)
+                    cond-name
+                    (cond-op cond-operation)
+                    (parse-long cond-val)])
+                 core/split-whitespace)
+                (input-manager/get-input 2017 8)))
+
+(defn compute [acc [reg reg-op val cond-reg cond-op cond-val]]
+  (if (cond-op (acc cond-reg 0) cond-val)
+    (assoc acc reg (reg-op (acc reg 0) val))
+    acc))
+
+;; part 1
+(->> input
+    (reduce compute {})
+    (sort-by second)
+    last
+    second)
+
+;; part 2
+(->> input
+     (reductions compute {})
+     (mapcat identity)
+     set
+     (sort-by second)
+     last
+     second)
+

2017/src/day09.clj

@@ -0,0 +1,34 @@
+(ns day09
+  (:require [clojure.string :as str]
+            core
+            input-manager))
+
+(def input (input-manager/get-input-raw 2017 9))
+
+(defn sum-recursive-depths [s sum idx depth]
+  (if (>= idx (count s))
+    sum
+    (condp = (.charAt s idx)
+      \, (recur s sum (inc idx) depth)
+      \{ (recur s
+                (+ sum depth)
+                (inc idx)
+                (inc depth))
+      \} (recur s
+                sum
+                (inc idx)
+                (max (dec depth) 0)))))
+
+(defn exlam-canceler [s] (str/replace s #"!." ""))
+(def angle-bracket-regex #"<[^>]*>")
+
+(-> input
+    exlam-canceler
+    (str/replace angle-bracket-regex "")
+    (sum-recursive-depths 0 0 1))
+
+(->> input
+     exlam-canceler
+     (re-seq angle-bracket-regex)
+     (map #(- (count %) 2))
+     (reduce +))

2017/src/day11.clj

@@ -0,0 +1,27 @@
+(ns day11
+  (:require [core]
+            input-manager
+            [clojure.string :as str]))
+
+(def input (-> (input-manager/get-input-raw 2017 11)
+               (str/split #",")))
+
+(def offsets {"n" [0 1]
+              "ne" [0.5 0.5]
+              "se" [0.5 -0.5]
+              "s"  [0 -1]
+              "sw" [-0.5 -0.5]
+              "nw" [-0.5 0.5]})
+
+(defn distance-from-origin [pos]
+  (let [[x y] (map abs pos)]
+    (+ (* x 2) (- y x))))
+
+
+(->> input
+     (map offsets)
+     (reductions #(map + %1 %2) [0 0])
+     (map distance-from-origin)
+     ((juxt last (partial apply max)))
+     (zipmap [:part-one :part-two]))
+

2017/src/day12.clj

@@ -0,0 +1,34 @@
+(ns day12
+  (:require
+   [clojure.string :as str]
+   core
+   input-manager
+   [clojure.set :refer [difference]]))
+
+(def input (->> (input-manager/get-input 2017 12)
+                (map #(str/replace % #"," ""))
+                (map core/split-whitespace)
+                (map (fn [[a _ & rst]]
+                       [(parse-long a) (mapv parse-long rst)]))
+                (into {})))
+
+(defn group-from-start [start]
+  (loop [visited #{}
+         queue [start]]
+    (if-not (seq queue)
+      visited
+      (let [[curr & rst] queue
+            ns (filter (complement visited) (input curr))]
+        (recur (into visited ns)
+               (concat rst ns))))))
+
+;; part one
+(count (group-from-start 0))
+
+;; part two
+(loop [ks (into #{} (keys input))
+       i 0]
+  (if-not (seq ks)
+    i
+    (recur (difference ks (group-from-start (first ks)))
+           (inc i))))

2017/src/day13.clj

@@ -0,0 +1,58 @@
+(ns day13
+  (:require
+   [clojure.string :as str]
+   [core]
+   [input-manager]))
+
+(def lengths (->> (input-manager/get-input 2017 13)
+                  (map (comp #(mapv parse-long %)
+                             #(str/split % #": ")))
+                  (into {})))
+
+(defn move-sensor [{:keys [idx depth increasing-depth] :as sensor}]
+  (let [[keep-moving reverse-step] (if increasing-depth [inc dec] [dec inc])
+        depth' (keep-moving depth)]
+    (if (or (> depth' (dec (lengths idx)))
+            (< depth' 0))
+      (-> sensor
+          (update :depth reverse-step)
+          (update :increasing-depth not))
+      (assoc sensor :depth depth'))))
+
+(def initial-sensors (->> lengths
+                          keys
+                          (map #(hash-map :depth 0
+                                          :idx %
+                                          :increasing-depth true))))
+
+(defn is-spotted-by-sensors [acc pos]
+  (some #(when (and (= (:idx %) pos)
+                    (= (:depth %) 0))
+           %)
+        (:sensors acc)))
+
+(->> lengths keys (apply max) inc range
+     (reduce (fn [acc pos]
+               (let [spotted (is-spotted-by-sensors acc pos)]
+                 (-> acc
+                     (update :sensors (partial map move-sensor))
+                     (update :solution + (if spotted
+                                           (* pos (lengths pos))
+                                           0)))))
+             {:sensors initial-sensors
+              :solution 0})
+     :solution)
+
+(loop [i 0
+       start-val initial-sensors]
+  (if
+   (= true
+      (->> lengths keys (apply max) inc range
+           (reduce (fn [acc pos]
+                     (let [spotted (is-spotted-by-sensors acc pos)]
+                       (if spotted
+                         (reduced true)
+                         (update acc :sensors (partial map move-sensor)))))
+                   {:sensors start-val})))
+    (recur (inc i) (map move-sensor start-val))
+    i))

2017/src/user.clj

@@ -0,0 +1,11 @@
+(ns user
+  (:require
+    [clojure.pprint :as pprint]))
+
+(defonce printer (bound-fn* pprint/pprint))
+(add-tap printer)
+
+(comment
+  ;; tap debugging
+  (remove-tap printer))
+

2024/src/day03.clj

@@ -1,37 +1,31 @@
 (ns day03
-  (:require [core :as c]
-            [input-manager :refer [get-input]]
+  (:require [input-manager]
             [clojure.string :as str]))
 
-(def input (str/join (get-input 3)))
+(def input (input-manager/get-input-raw 2024 3))
 
-(defn parse-muls
-  "takes in a string containing mul instructions
-  returns list of parsed integral multiplication results"
-  [s]
-  (->> (c/get-match-groups #"mul\((\d{1,3}),(\d{1,3})\)" s)
-       (map #(map parse-long %))
-       (map #(reduce * %))))
+(defn compute-muls [s]
+  (map (comp #(reduce * %)
+             #(map parse-long %)
+             #(str/split % #",")
+             #(subs % 4 (dec (count %)))) ;; remove `mul(` prefix and `)` suffix
+       s))
+
+(defn enforce-toggles [[el & rst]]
+  (cond (= el "do()")    (recur rst)
+        (= el "don't()") (recur (drop-while #(not= % "do()") rst))
+        el               (conj (lazy-seq (enforce-toggles rst)) el)))
 
 ;; part 1
 (->> input
-     parse-muls
+     (re-seq #"mul\(\d{1,3},\d{1,3}\)")
+     compute-muls
      (reduce +))
 
 ;; part 2
 (->> input
-     (c/re-pos #"mul\((\d{1,3}),(\d{1,3})\)|(do\(\))|(don't\(\))")
-     (sort-by key)
-     (reduce
-      (fn [acc [_idx instr]]
-        (cond
-          (.startsWith instr "mul") (if (:on acc)
-                                      (update acc :val
-                                              + (->> instr parse-muls first))
-                                      acc)
-          (.startsWith instr "don't") (assoc acc :on false)
-          (.startsWith instr "do") (assoc acc :on true)))
-      {:on true
-       :val 0})
-     :val)
+     (re-seq #"mul\(\d{1,3},\d{1,3}\)|do\(\)|don't\(\)")
+     enforce-toggles
+     compute-muls
+     (reduce +))
 

2025/.gitignore

@@ -1,3 +1,4 @@
 input/
 .lein-repl-history
+.idea/
 *.iml

2025/project.clj

@@ -9,5 +9,7 @@
                  [org.clojure/math.combinatorics "0.3.0"]
                  [babashka/fs "0.5.23"]
                  [org.babashka/http-client "0.4.22"]
-                 [org.clojure/core.match "1.1.0"]]
-  :source-paths ["src" "../shared/clj/src"])
+                 [org.clojure/core.match "1.1.0"]
+                 [clj-python/libpython-clj "2.025"]
+                 [tools.aqua/z3-turnkey "4.14.1"]]
+ :source-paths ["src" "../shared/clj/src"])

2025/src/day09.clj

@@ -1,56 +1,51 @@
 (ns day09
-  (:require input-manager))
+  (:require [input-manager]))
 
 (def input (->> (input-manager/get-input 2025 9)
                 (mapv #(mapv parse-long (re-seq #"\d+" %)))))
-
 (defn area [[ax ay] [bx by]]
   (* (inc (abs (- ax bx)))
      (inc (abs (- ay by)))))
-(def furthest-points
-  (->> (for [a input
-             b input
-             :when (not= a b)]
-         #{a b})
-       distinct
-       (map vec)
-       (sort-by #(apply area %))))
-
+(def largest-rects (->> (for [a input
+                              b input
+                              :when (not= a b)]
+                          #{a b})
+                        distinct
+                        (map vec)
+                        (sort-by #(apply area %))))
 ;; part 1
-(->> furthest-points
+(->> largest-rects
      last
      (apply area))
 
 (defn normalize [x] (min 1 (max -1 x)))
 (defn orientation
-  "returns a value indicating if point A is to the left, right, or on the line BC"
+  "returns a value indicating if point B is to the left, right, or on the line AC"
   [[ax ay] [bx by] [cx cy]]
   (normalize (- (* (- by ay) (- cx bx))
                 (* (- bx ax) (- cy by)))))
-
 (defn intersect?
   "Lines AB and CD intersect if points A and B falls on different sides of CD
   and if C and D fall on different sides of AB"
   [[a b] [c d]]
-  (let [o1 (orientation a b c)
-        o2 (orientation a b d)
-        o3 (orientation c d a)
-        o4 (orientation c d b)]
+  (let [o1 (orientation a c b)
+        o2 (orientation a d b)
+        o3 (orientation c a d)
+        o4 (orientation c b d)]
     (and (not= o1 o2) (not= o3 o4))))
+(def line-segments (map vector input (rest input)))
 
 ;; part 2
-(def line-segments (map vector input (conj (vec (rest input)) (first input))))
-(->> furthest-points
-     (filter (fn [[a b]]
-               (let [segments (filter (fn [[seg-a seg-b]] (and (not= a seg-a)
-                                                               (not= a seg-b)
-                                                               (not= b seg-a)
-                                                               (not= b seg-b)))
+(->> largest-rects
+     (filter (fn [[a b :as rect]]
+               (let [segments (filter (fn overlapping? [[c d]]
+                                        (and (not= a c) (not= a d)
+                                             (not= b c) (not= b d))) ;; filter out segments that include points a or b
                                       line-segments)
-                     [[cx cy] [dx dy]] [a b]]
-                 (and (not (some #(intersect? [a b] %) segments))
-                      (not (some #(intersect? [[cx dy] [dx cy]] %) segments))))))
-     (sort-by (partial apply area))
-     last
-     (apply area))
-
+                     [[cx cy] [dx dy]] rect
+                     reverse-diag [[cx dy] [dx cy]]]
+                 (and (not (some #(intersect? rect %) segments))
+                      (not (some #(intersect? reverse-diag %) segments))))))
+     (map (partial apply area))
+     sort
+     last)

2025/src/day10.clj

@@ -0,0 +1,71 @@
+(ns day10
+  (:require [clojure.math.combinatorics :as combo]
+            [input-manager])
+  (:import (com.microsoft.z3 Context Expr IntNum Optimize Optimize$Handle)))
+
+(defn parse-line [line]
+  {:indicators (->> line
+                    (drop 1)
+                    (take-while (complement #{\]}))
+                    (mapv (partial = \#)))
+   :buttons    (->> line
+                    (re-seq #"\([\d,]+\)")
+                    (map #(map parse-long (re-seq #"\d+" %))))
+   :joltages   (->> line
+                    (drop-while #(not= % \{))
+                    (drop 1)
+                    (take-while #(not= % \}))
+                    (apply str)
+                    (re-seq #"\d+")
+                    (mapv parse-long))})
+
+(def input (map parse-line (input-manager/get-input 2025 10)))
+
+(defn minimum-button-mashing [{:keys [buttons indicators]}]
+  (loop [i 0
+         cnt 1]
+    (if (>= i (combo/count-combinations buttons cnt))
+      (recur 0 (inc cnt))
+      (let [indicators' (reduce (partial reduce #(update %1 %2 not))
+                                indicators
+                                (combo/nth-combination buttons cnt i))]
+        (if (every? (complement identity) indicators')
+          cnt
+          (recur (inc i) cnt))))))
+
+;; part 1
+(apply + (map minimum-button-mashing input))
+
+;; part 2
+(defn add-expressions [opt expressions]
+  (.Add opt (into-array Expr expressions)))
+
+(->> input
+     (map (fn [{:keys [joltages buttons]}]
+            (let [ctx (Context.)
+                  ^Optimize opt (.mkOptimize ctx)
+                  bs (->> buttons
+                          count
+                          range
+                          (map #(.mkIntConst ctx (str "b" %))))
+                  js (->> joltages
+                          count
+                          range
+                          (map #(.mkIntConst ctx (str "j" %))))]
+              (add-expressions opt (for [idx (range (count joltages))]
+                                     (.mkEq ctx (nth js idx) (->> buttons
+                                                                  (map set)
+                                                                  (map-indexed vector)
+                                                                  (filter #(contains? (second %) idx))
+                                                                  (map first)
+                                                                  (map #(nth bs %))
+                                                                  (into-array Expr)
+                                                                  (.mkAdd ctx)))))
+              (add-expressions opt (for [[idx joltage] (map-indexed vector joltages)]
+                                     (.mkEq ctx (nth js idx) (.mkInt ctx (long joltage)))))
+              (add-expressions opt (for [b bs]
+                                     (.mkGe ctx b (.mkInt ctx (long 0)))))
+              (let [^Optimize$Handle mx (.MkMinimize opt (.mkAdd ctx (into-array Expr bs)))]
+                (.Check opt (into-array Expr []))
+                (.getInt ^IntNum (.getValue mx))))))
+     (apply +))

2025/src/day11.clj

@@ -0,0 +1,21 @@
+(ns day11
+  (:require [input-manager]))
+
+(def input (->> (input-manager/get-input 2025 11)
+                (map (comp (fn [[node & edges]]
+                             [node (into #{} edges)])
+                           (partial re-seq #"[a-z]{3}")))
+                (into {})))
+
+(def count-paths (memoize (fn [start target]
+                            (let [edges (input start)]
+                              (if (contains? edges target)
+                                1
+                                (apply + (map #(count-paths % target) edges)))))))
+
+;; part 1
+(count-paths "you" "out")
+
+;; part 2
+(+ (* (count-paths "svr" "dac") (count-paths "dac" "fft") (count-paths "fft" "out"))
+   (* (count-paths "svr" "fft") (count-paths "fft" "dac") (count-paths "dac" "out")))

2025/src/day12.clj

@@ -0,0 +1,84 @@
+(ns day12
+  (:require input-manager
+            core
+            [clojure.string :as str]
+            clojure.set))
+
+(def requirements (->> (input-manager/get-input-raw 2025 12)
+                       (core/split-on-double-newlines)
+                       (map str/split-lines)
+                       last
+                       (map (comp (fn [[x y & cnts]]
+                                    [[x y] (into {} (map-indexed vector cnts))])
+                                  (partial map parse-long)
+                                  (partial re-seq #"\d+")))))
+
+(defn fits-trivially?
+  "is it trivially possible to fit all the pieces if they were 3x3 blocks instead of jigsaws"
+  [[dimensions cnts]]
+  (let [area (apply * dimensions)
+        guess (->> cnts vals (reduce +) (* 9))]
+    (>= area guess)))
+
+;; part 1
+(->> requirements
+     (filter fits-trivially?)
+     count)
+
+(comment
+  ;; NP Hard... general solution is not fast enough
+  (defn flip [grid]
+    (vec (reverse grid)))
+  (defn rotations [grid]
+    (->> [(for [x (range 0 3)]
+            (for [y (range 0 3)]
+              (.charAt (grid x) y)))
+          (for [y (range 2 -1 -1)]
+            (for [x (range 0 3)]
+              (.charAt (grid x) y)))
+          (for [x (range 2 -1 -1)]
+            (for [y (range 2 -1 -1)]
+              (.charAt (grid x) y)))
+          (for [y (range 2 -1 -1)]
+            (for [x (range 3)]
+              (.charAt (grid x) y)))]
+         (map (partial map-indexed (fn [row-idx row]
+                                     (map-indexed (fn [col-idx cell]
+                                                    (when (= cell \#)
+                                                      [row-idx col-idx]))
+                                                  row))))
+         (map (partial mapcat (partial filter identity)))
+         (mapv (partial mapv vec))
+         set))
+
+  #_(def jigsaws (->> (drop-last (->> (input-manager/get-input-raw 2025 12)
+                                      (core/split-on-double-newlines)
+                                      (map str/split-lines)))
+                      (map (fn [[idx & puzzle-lines]]
+                             [(parse-long (apply str (drop-last idx)))
+                              (clojure.set/union (rotations (vec puzzle-lines)) (rotations (flip puzzle-lines)))]))
+                      (into {})))
+  (defn placeable? [jigsaw filled]
+    (every? #(not (contains? filled %)) jigsaw))
+
+  (defn offset [loc jigsaw]
+    (into #{} (map #(mapv + % loc) jigsaw)))
+
+  (defn fits? [[[rows cols :as dimensions] cnts] jigsaws filled]
+    (cond
+      (every? (partial = 0) (vals cnts)) true
+      :else
+      (let [[id] (first (filter (fn [[_ cnt]] (> cnt 0)) cnts))
+            orientations (jigsaws id)
+            locs (for [row (range (- rows 2))
+                       col (range (- cols 2))]
+                   [row col])
+            cnts' (update cnts id dec)]
+        (some (fn [loc]
+                (->> orientations
+                     (map #(offset loc %))
+                     (filter #(placeable? % filled))
+                     (map #(fits? [dimensions cnts'] jigsaws (clojure.set/union filled %)))
+                     (filter identity)
+                     first))
+              locs)))))

2025/src/user.clj

@@ -0,0 +1,11 @@
+(ns user
+  (:require
+    [clojure.pprint :as pprint]))
+
+(defonce printer (bound-fn* pprint/pprint))
+(add-tap printer)
+
+(comment
+  ;; tap debugging
+  (remove-tap printer))
+