Ch83 (Clojure): Task 2

4 files changed, 69 insertions, 3 deletions

diff --git a/challenge-083/tyler-wardhaugh/clojure/deps.edn b/challenge-083/tyler-wardhaugh/clojure/deps.edn
index 4d1263a667..e3e3cdbca6 100644
--- a/challenge-083/tyler-wardhaugh/clojure/deps.edn
+++ b/challenge-083/tyler-wardhaugh/clojure/deps.edn
@@ -1,5 +1,7 @@
 {:paths ["src" "resources"]
- :deps {org.clojure/clojure {:mvn/version "1.10.1"}}
+ :deps {org.clojure/clojure {:mvn/version "1.10.1"}
+        org.clojure/math.combinatorics {:mvn/version "0.1.6"}
+        net.cgrand/xforms {:mvn/version "0.19.2"}}
  :aliases
  {:test {:extra-paths ["test"]
          :extra-deps {org.clojure/test.check {:mvn/version "1.0.0"}}}
diff --git a/challenge-083/tyler-wardhaugh/clojure/src/tw/weekly/c83/core.clj b/challenge-083/tyler-wardhaugh/clojure/src/tw/weekly/c83/core.clj
index 03b7eadc2c..d25ddca2de 100644
--- a/challenge-083/tyler-wardhaugh/clojure/src/tw/weekly/c83/core.clj
+++ b/challenge-083/tyler-wardhaugh/clojure/src/tw/weekly/c83/core.clj
@@ -1,9 +1,12 @@
 (ns tw.weekly.c83.core
   (:require [tw.weekly.c83.t1 :as t1])
+  (:require [tw.weekly.c83.t2 :as t2])
   (:gen-class))
 
 (defn -main
   "Run all tasks"
   [& _]
   (println "Task #1")
-  (t1/-main))
+  (t1/-main)
+  (println "Task #2")
+  (t2/-main))
diff --git a/challenge-083/tyler-wardhaugh/clojure/src/tw/weekly/c83/t2.clj b/challenge-083/tyler-wardhaugh/clojure/src/tw/weekly/c83/t2.clj
new file mode 100644
index 0000000000..1dc22c8372
--- /dev/null
+++ b/challenge-083/tyler-wardhaugh/clojure/src/tw/weekly/c83/t2.clj
@@ -0,0 +1,55 @@
+(ns tw.weekly.c83.t2
+  (:require [clojure.edn :as edn])
+  (:require [clojure.math.combinatorics :as combo])
+  (:require [net.cgrand.xforms :as x]))
+
+;;; Task description for
+; TASK #2 › Flip Array
+; Submitted by: Mohammad S Anwar
+; You are given an array @A of positive numbers.
+;
+; Write a script to flip the sign of some members of the given array so that
+; the sum of the all members is minimum non-negative.
+;
+; Given an array of positive elements, you have to flip the sign of some of its
+; elements such that the resultant sum of the elements of array should be
+; minimum non-negative(as close to zero as possible). Return the minimum no. of
+; elements whose sign needs to be flipped such that the resultant sum is
+; minimum non-negative.
+;
+; Example 1:
+; Input: @A = (3, 10, 8)
+; Output: 1
+
+; Explanation:
+; Flipping the sign of just one element 10 gives the result 1 i.e. (3) + (-10) + (8) = 1
+;
+;
+; Example 2:
+; Input: @A = (12, 2, 10)
+; Output: 1
+;
+; Explanation:
+; Flipping the sign of just one element 12 gives the result 0 i.e. (-12) + (2) + (10) = 0
+;
+;;;
+
+(defn flip-array
+  "Determine the minimum number of 'flips' needed to produce the smallest non-negative sum."
+  [coll]
+  (let [source (->> coll (map (juxt - +)) (apply combo/cartesian-product))
+        xf (comp
+             (x/by-key (partial reduce +) (x/into []))
+             (remove (comp neg? first))
+             x/min
+             x/vals
+             cat
+             (map (comp count (partial filter neg?))))]
+    (reduce min ##Inf (eduction xf source))))
+
+(defn -main
+  "Run Task 2 with an array of integers, defaulting to the example given in the task description."
+  [& args]
+  (let [A (or (some->> args (map edn/read-string)) [3 10 8])
+        minimum (flip-array A)]
+    (println minimum)))
diff --git a/challenge-083/tyler-wardhaugh/clojure/test/tw/weekly/c83_test.clj b/challenge-083/tyler-wardhaugh/clojure/test/tw/weekly/c83_test.clj
index 870b3e6164..ff8aafb9bb 100644
--- a/challenge-083/tyler-wardhaugh/clojure/test/tw/weekly/c83_test.clj
+++ b/challenge-083/tyler-wardhaugh/clojure/test/tw/weekly/c83_test.clj
@@ -1,9 +1,15 @@
 (ns tw.weekly.c83-test
   (:require [clojure.test :refer [deftest is testing]]
-            [tw.weekly.c83.t1 :refer [inner-words-length]]))
+            [tw.weekly.c83.t1 :refer [inner-words-length]]
+            [tw.weekly.c83.t2 :refer [flip-array]]))
 
 (deftest task-1
   (testing "Task 1, Words Length"
     (is (= (inner-words-length "The Weekly Challenge") 6))
     (is (= (inner-words-length  "The purpose of our lives is to be happy") 23))
     (is (= (inner-words-length  "Zero when-no-inner-words-exist!") 0))))
+
+(deftest task-2
+  (testing "Task 2, Flip Array"
+    (is (= (flip-array [3 10 8]) 1))
+    (is (= (flip-array [12 2 10]) 1))))