move 2021 days to folder; update README

1 files changed, 70 insertions, 0 deletions

diff --git a/year2021/day4/part2.clj b/year2021/day4/part2.clj
new file mode 100644
index 0000000..516e83c
--- /dev/null
+++ b/year2021/day4/part2.clj
@@ -0,0 +1,70 @@
+(require '[clojure.string :as str])
+
+(def calls
+  (->> (read-line)
+       (#(str/split % #","))
+       (map #(Integer/parseInt %))
+       )
+  )
+
+(defn read-board []
+  (when (some? (read-line))
+    (mapv
+        (fn [line] (->> line
+            (str/join)
+            (str/trim)
+            (#(str/split % #"\s+"))
+            (map #(Integer/parseInt %))
+            )
+          )
+        (repeatedly 5 read-line)
+        )
+    )
+  )
+
+(defn bingo? [board]
+  (some?
+    (some
+      #(every? nil? %)
+      (concat board (apply mapv vector board))
+      )
+    )
+  )
+
+(defn bingo-mark [board n]
+  (mapv (partial replace {n nil}) board)
+  )
+
+(defn get-bingo [init-board]
+  (loop [board init-board nums calls turns 1]
+    (let [new-board (bingo-mark board (first nums))]
+      (if (bingo? new-board)
+        [new-board (first nums) turns]
+        (recur new-board (rest nums) (inc turns))
+        )
+      )
+    )
+  )
+
+(loop [best [0 0] board (read-board)]
+  (if (nil? board)
+    (println best)
+    (let [bingo (get-bingo board)]
+      (recur
+        (if (> (get bingo 2) (first best))
+          [(get bingo 2)
+           (->> (first bingo)
+                (flatten)
+                (filter some?)
+                (apply +)
+                (* (second bingo))
+                )
+           ]
+          best
+          )
+        (read-board)
+        )
+      )
+    )
+  )
+