Add resistor-color-trio exercise (#794)

* Add `resistor-color-trio` exercise

* Update exercises/practice/resistor-color-trio/src/resistor_color_trio.clj

Co-authored-by: Anastasios Chatzialexiou <[email protected]>

* Tweaks

---------

Co-authored-by: Anastasios Chatzialexiou <[email protected]>

config.json

@@ -1277,6 +1277,19 @@
         ],
         "difficulty": 5
       },
+      {
+        "slug": "resistor-color-trio",
+        "name": "Resistor Color Trio",
+        "uuid": "4f8bc34b-59bd-4a93-a120-d5e5ee3bd4a3",
+        "practices": [],
+        "prerequisites": [
+          "numbers",
+          "vectors",
+          "strings",
+          "conditionals"
+        ],
+        "difficulty": 5
+      },
       {
         "slug": "list-ops",
         "name": "List Ops",

exercises/practice/resistor-color-trio/.docs/instructions.md

@@ -0,0 +1,56 @@
+# Instructions
+
+If you want to build something using a Raspberry Pi, you'll probably use _resistors_.
+For this exercise, you need to know only three things about them:
+
+- Each resistor has a resistance value.
+- Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.
+  To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values.
+- Each band acts as a digit of a number.
+  For example, if they printed a brown band (value 1) followed by a green band (value 5), it would translate to the number 15.
+  In this exercise, you are going to create a helpful program so that you don't have to remember the values of the bands.
+  The program will take 3 colors as input, and outputs the correct value, in ohms.
+  The color bands are encoded as follows:
+
+- black: 0
+- brown: 1
+- red: 2
+- orange: 3
+- yellow: 4
+- green: 5
+- blue: 6
+- violet: 7
+- grey: 8
+- white: 9
+
+In Resistor Color Duo you decoded the first two colors.
+For instance: orange-orange got the main value `33`.
+The third color stands for how many zeros need to be added to the main value.
+The main value plus the zeros gives us a value in ohms.
+For the exercise it doesn't matter what ohms really are.
+For example:
+
+- orange-orange-black would be 33 and no zeros, which becomes 33 ohms.
+- orange-orange-red would be 33 and 2 zeros, which becomes 3300 ohms.
+- orange-orange-orange would be 33 and 3 zeros, which becomes 33000 ohms.
+
+(If Math is your thing, you may want to think of the zeros as exponents of 10.
+If Math is not your thing, go with the zeros.
+It really is the same thing, just in plain English instead of Math lingo.)
+
+This exercise is about translating the colors into a label:
+
+> "... ohms"
+
+So an input of `"orange", "orange", "black"` should return:
+
+> "33 ohms"
+
+When we get to larger resistors, a [metric prefix][metric-prefix] is used to indicate a larger magnitude of ohms, such as "kiloohms".
+That is similar to saying "2 kilometers" instead of "2000 meters", or "2 kilograms" for "2000 grams".
+
+For example, an input of `"orange", "orange", "orange"` should return:
+
+> "33 kiloohms"
+
+[metric-prefix]: https://en.wikipedia.org/wiki/Metric_prefix

exercises/practice/resistor-color-trio/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "src/resistor_color_trio.clj"
+    ],
+    "test": [
+      "test/resistor_color_trio_test.clj"
+    ],
+    "example": [
+      ".meta/example.clj"
+    ]
+  },
+  "blurb": "Convert color codes, as used on resistors, to a human-readable label.",
+  "source": "Maud de Vries, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1549"
+}

exercises/practice/resistor-color-trio/.meta/example.clj

@@ -0,0 +1,25 @@
+(ns resistor-color-trio)
+
+(def colors ["black" "brown" "red" "orange" "yellow" "green" "blue" "violet" "grey" "white"])
+
+(defn- color->value [color] (.indexOf colors color))
+
+(defn- pow [a b] (reduce * (repeat b a)))
+
+(defn- colors->value [colors]
+  (let [[value-1 value-2 value-3] (map color->value colors)]
+    (* (+ (* 10 value-1) value-2) (pow 10 value-3))))
+
+(def units [nil "kilo" "mega" "giga"])
+
+(defn unit-label [[amount unit]] (str amount " " unit "ohms"))
+
+(defn resistor-label [colors]
+  (let [value (colors->value colors)]
+    (->> units
+         (map-indexed vector)
+         (some
+          (fn [[idx unit]]
+            (when (<= value (pow 1000 (inc idx)))
+              [(quot value (pow 1000 idx)) unit])))
+         (unit-label))))

exercises/practice/resistor-color-trio/.meta/generator.clj

@@ -0,0 +1,4 @@
+(ns resistor-color-trio-generator)
+
+(defn update-test-case [test-case]
+  (update test-case :expected #(str (:value %) " " (:unit %))))

exercises/practice/resistor-color-trio/.meta/generator.tpl

@@ -0,0 +1,9 @@
+(ns resistor-color-trio-test
+  (:require [clojure.test :refer [deftest testing is]]
+            resistor-color-trio))
+
+{{#test_cases.label}}
+(deftest resistor-label_test_{{idx}}
+  (testing {{description}}
+    (is (= {{expected}} (resistor-color-trio/resistor-label {{input.colors}})))))
+{{/test_cases.label}}

exercises/practice/resistor-color-trio/.meta/tests.toml

@@ -0,0 +1,40 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[d6863355-15b7-40bb-abe0-bfb1a25512ed]
+description = "Orange and orange and black"
+
+[1224a3a9-8c8e-4032-843a-5224e04647d6]
+description = "Blue and grey and brown"
+
+[b8bda7dc-6b95-4539-abb2-2ad51d66a207]
+description = "Red and black and red"
+
+[5b1e74bc-d838-4eda-bbb3-eaba988e733b]
+description = "Green and brown and orange"
+
+[f5d37ef9-1919-4719-a90d-a33c5a6934c9]
+description = "Yellow and violet and yellow"
+
+[5f6404a7-5bb3-4283-877d-3d39bcc33854]
+description = "Blue and violet and blue"
+
+[7d3a6ab8-e40e-46c3-98b1-91639fff2344]
+description = "Minimum possible value"
+
+[ca0aa0ac-3825-42de-9f07-dac68cc580fd]
+description = "Maximum possible value"
+
+[0061a76c-903a-4714-8ce2-f26ce23b0e09]
+description = "First two colors make an invalid octal number"
+
+[30872c92-f567-4b69-a105-8455611c10c4]
+description = "Ignore extra colors"

exercises/practice/resistor-color-trio/deps.edn

@@ -0,0 +1,6 @@
+{:aliases {:test {:extra-paths ["test"]
+                 :extra-deps {io.github.cognitect-labs/test-runner 
+                              {:git/url "https://github.com/cognitect-labs/test-runner.git"
+                               :sha "705ad25bbf0228b1c38d0244a36001c2987d7337"}}
+                 :main-opts ["-m" "cognitect.test-runner"]
+                 :exec-fn cognitect.test-runner.api/test}}}

exercises/practice/resistor-color-trio/project.clj

@@ -0,0 +1,4 @@
+(defproject resistor-color-trio "0.1.0-SNAPSHOT"
+  :description "resistor-color-trio exercise."
+  :url "https://github.com/exercism/clojure/tree/main/exercises/practice/resistor-color-trio"
+  :dependencies [[org.clojure/clojure "1.11.1"]])

exercises/practice/resistor-color-trio/src/resistor_color_trio.clj

@@ -0,0 +1,7 @@
+(ns resistor-color-trio)
+
+(defn resistor-label
+  "Returns the resistor label based on the given color bands."
+  [colors]
+  ;; function body
+  )

exercises/practice/resistor-color-trio/test/resistor_color_trio_test.clj

@@ -0,0 +1,43 @@
+(ns resistor-color-trio-test
+  (:require [clojure.test :refer [deftest testing is]]
+            resistor-color-trio))
+
+(deftest resistor-label_test_1
+  (testing "Orange and orange and black"
+    (is (= "33 ohms" (resistor-color-trio/resistor-label ["orange" "orange" "black"])))))
+
+(deftest resistor-label_test_2
+  (testing "Blue and grey and brown"
+    (is (= "680 ohms" (resistor-color-trio/resistor-label ["blue" "grey" "brown"])))))
+
+(deftest resistor-label_test_3
+  (testing "Red and black and red"
+    (is (= "2 kiloohms" (resistor-color-trio/resistor-label ["red" "black" "red"])))))
+
+(deftest resistor-label_test_4
+  (testing "Green and brown and orange"
+    (is (= "51 kiloohms" (resistor-color-trio/resistor-label ["green" "brown" "orange"])))))
+
+(deftest resistor-label_test_5
+  (testing "Yellow and violet and yellow"
+    (is (= "470 kiloohms" (resistor-color-trio/resistor-label ["yellow" "violet" "yellow"])))))
+
+(deftest resistor-label_test_6
+  (testing "Blue and violet and blue"
+    (is (= "67 megaohms" (resistor-color-trio/resistor-label ["blue" "violet" "blue"])))))
+
+(deftest resistor-label_test_7
+  (testing "Minimum possible value"
+    (is (= "0 ohms" (resistor-color-trio/resistor-label ["black" "black" "black"])))))
+
+(deftest resistor-label_test_8
+  (testing "Maximum possible value"
+    (is (= "99 gigaohms" (resistor-color-trio/resistor-label ["white" "white" "white"])))))
+
+(deftest resistor-label_test_9
+  (testing "First two colors make an invalid octal number"
+    (is (= "8 ohms" (resistor-color-trio/resistor-label ["black" "grey" "black"])))))
+
+(deftest resistor-label_test_10
+  (testing "Ignore extra colors"
+    (is (= "650 kiloohms" (resistor-color-trio/resistor-label ["blue" "green" "yellow" "orange"])))))