Solution for both parts of the problem from day 11

Author: rvprasad

day11/README.md

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+Execute this code via `clj -M -m day11 <filename>`.
+
+### Observations
+

day11/src/day11.clj

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+(ns day11
+  (:require [clojure.string :as str])
+  (:require [clojure.core.reducers :as reducers]))
+
+(defn calculate-sum-of-distance [lines scale]
+  (let [rows (into [] (map (fn [x] (str/split x #"")) lines))
+        expanding-rows (map first (filter (fn [[idx va]] (every? #(= "." %1) va))
+                                          (map-indexed list rows)))
+        cols (apply mapv vector rows)
+        expanding-cols (map first (filter (fn [[idx va]] (every? #(= "." %1) va))
+                                          (map-indexed list cols)))
+        galaxies (filter (fn [[r c]] (= (get (get rows r) c) "#"))
+                         (apply concat (map
+                                        (fn [r] (map #(list r %1) (range (count cols))))
+                                        (range (count rows)))))
+        count-in-range (fn [vals lo hi]
+                         (count (filter #(and (< lo %1) (< %1 hi)) vals)))
+        calc-distance (fn [[[r1 c1] [r2 c2]]]
+                        (let [calc-axis-parallel-distance
+                              (fn [a b expaning-elems]
+                                (let [num-of-expanding-elems
+                                      (count-in-range expaning-elems (min a b) (max a b))
+                                      raw-distance (abs (- a b))]
+                                  (+ (- raw-distance num-of-expanding-elems)
+                                     (* scale num-of-expanding-elems))))]
+                          (+ (calc-axis-parallel-distance r1 r2 expanding-rows)
+                             (calc-axis-parallel-distance c1 c2 expanding-cols))))
+        cross-product (apply concat (for [g1 galaxies]
+                                      (for [g2 galaxies
+                                            :when (not (= g1 g2))]
+                                        [g1 g2])))]
+
+    (println (/ (reducers/fold + (map calc-distance cross-product)) 2))))
+
+(defn -main [filename]
+  (with-open [file (clojure.java.io/reader filename)]
+    (let [lines (remove str/blank? (line-seq file))]
+      (calculate-sum-of-distance lines 2)
+      (calculate-sum-of-distance lines 1000000))))