Add resistor-color-duo (#862)

Author: Sencudra

config.json

@@ -520,6 +520,14 @@
           "text_formatting"
         ]
       },
+      {
+        "slug": "resistor-color-duo",
+        "name": "Resistor Color Duo",
+        "uuid": "e6b8cbce-c75b-492c-aca4-2a078837bb9d",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "binary-search",
         "name": "Binary Search",

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

@@ -0,0 +1,33 @@
+# Instructions
+
+If you want to build something using a Raspberry Pi, you'll probably use _resistors_.
+For this exercise, you need to know two 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 has a position and a numeric value.
+
+The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single 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 color names as input and output a two digit number, even if the input is more than two colors!
+
+The band colors are encoded as follows:
+
+- black: 0
+- brown: 1
+- red: 2
+- orange: 3
+- yellow: 4
+- green: 5
+- blue: 6
+- violet: 7
+- grey: 8
+- white: 9
+
+From the example above:
+brown-green should return 15, and
+brown-green-violet should return 15 too, ignoring the third color.

exercises/practice/resistor-color-duo/.meta/Sources/ResistorColorDuo/ResistorColorDuoExample.swift

@@ -0,0 +1,49 @@
+import Foundation
+
+enum Color: String, CaseIterable {
+    case black
+    case brown
+    case red
+    case orange
+    case yellow
+    case green
+    case blue
+    case violet
+    case grey
+    case white
+}
+
+enum ResistorColorDuoError: Error {
+    case unknownColor
+}
+
+enum ResistorColorDuo {
+
+    static func value(for colors: [String]) throws -> Int {
+        var result = 0
+        for index in 0..<min(colors.count, 2) {
+            guard let color = Color(rawValue: colors[index]) else {
+                throw ResistorColorDuoError.unknownColor
+            }
+            let value = code(for: color)
+            result = result * 10 + value
+        }
+        return result 
+    }
+
+}
+
+fileprivate func code(for color: Color) -> Int {
+    switch color {
+        case .black: return 0
+        case .brown: return 1
+        case .red: return 2
+        case .orange: return 3
+        case .yellow: return 4
+        case .green: return 5
+        case .blue: return 6
+        case .violet: return 7
+        case .grey: return 8
+        case .white: return 9
+    }
+}

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

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "Sencudra"
+  ],
+  "files": {
+    "solution": [
+      "Sources/ResistorColorDuo/ResistorColorDuo.swift"
+    ],
+    "test": [
+      "Tests/ResistorColorDuoTests/ResistorColorDuoTests.swift"
+    ],
+    "example": [
+      ".meta/Sources/ResistorColorDuo/ResistorColorDuoExample.swift"
+    ]
+  },
+  "blurb": "Convert color codes, as used on resistors, to a numeric value.",
+  "source": "Maud de Vries, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1464"
+}

exercises/practice/resistor-color-duo/.meta/template.swift

@@ -0,0 +1,18 @@
+import Testing
+import Foundation
+@testable import {{ exercise | camelCase }}
+
+let RUNALL = Bool(ProcessInfo.processInfo.environment["RUNALL", default: "false"]) ?? false
+
+@Suite struct {{ exercise | camelCase }}Tests {
+    {% for case in cases %}
+    {% if forloop.first -%}
+        @Test("{{case.description}}")
+    {% else -%}
+        @Test("{{case.description}}", .enabled(if: RUNALL))
+    {% endif -%}
+    func test{{ case.description | camelCase }}() throws {
+        #expect(try ResistorColorDuo.{{ case.property }}(for: {{ case.input.colors | toStringArray }}) == {{ case.expected }})
+    }
+    {% endfor -%}
+}

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

@@ -0,0 +1,31 @@
+# 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.
+
+[ce11995a-5b93-4950-a5e9-93423693b2fc]
+description = "Brown and black"
+
+[7bf82f7a-af23-48ba-a97d-38d59406a920]
+description = "Blue and grey"
+
+[f1886361-fdfd-4693-acf8-46726fe24e0c]
+description = "Yellow and violet"
+
+[b7a6cbd2-ae3c-470a-93eb-56670b305640]
+description = "White and red"
+
+[77a8293d-2a83-4016-b1af-991acc12b9fe]
+description = "Orange and orange"
+
+[0c4fb44f-db7c-4d03-afa8-054350f156a8]
+description = "Ignore additional colors"
+
+[4a8ceec5-0ab4-4904-88a4-daf953a5e818]
+description = "Black and brown, one-digit"

exercises/practice/resistor-color-duo/Package.swift

@@ -0,0 +1,21 @@
+// swift-tools-version:6.0
+
+import PackageDescription
+
+let package = Package(
+  name: "ResistorColorDuo",
+  products: [
+    .library(
+      name: "ResistorColorDuo",
+      targets: ["ResistorColorDuo"])
+  ],
+  dependencies: [],
+  targets: [
+    .target(
+      name: "ResistorColorDuo",
+      dependencies: []),
+    .testTarget(
+      name: "ResistorColorDuoTests",
+      dependencies: ["ResistorColorDuo"]),
+  ]
+)

exercises/practice/resistor-color-duo/Sources/ResistorColorDuo/ResistorColorDuo.swift

@@ -0,0 +1,5 @@
+import Foundation
+
+enum ResistorColorDuo {
+    // Write your code for the 'ResistorColorDuo' exercise in this file.
+}

exercises/practice/resistor-color-duo/Tests/ResistorColorDuoTests/ResistorColorDuoTests.swift

@@ -0,0 +1,44 @@
+import Foundation
+import Testing
+
+@testable import ResistorColorDuo
+
+let RUNALL = Bool(ProcessInfo.processInfo.environment["RUNALL", default: "false"]) ?? false
+
+@Suite struct ResistorColorDuoTests {
+
+  @Test("Brown and black")
+  func testBrownAndBlack() throws {
+    #expect(try ResistorColorDuo.value(for: ["brown", "black"]) == 10)
+  }
+
+  @Test("Blue and grey", .enabled(if: RUNALL))
+  func testBlueAndGrey() throws {
+    #expect(try ResistorColorDuo.value(for: ["blue", "grey"]) == 68)
+  }
+
+  @Test("Yellow and violet", .enabled(if: RUNALL))
+  func testYellowAndViolet() throws {
+    #expect(try ResistorColorDuo.value(for: ["yellow", "violet"]) == 47)
+  }
+
+  @Test("White and red", .enabled(if: RUNALL))
+  func testWhiteAndRed() throws {
+    #expect(try ResistorColorDuo.value(for: ["white", "red"]) == 92)
+  }
+
+  @Test("Orange and orange", .enabled(if: RUNALL))
+  func testOrangeAndOrange() throws {
+    #expect(try ResistorColorDuo.value(for: ["orange", "orange"]) == 33)
+  }
+
+  @Test("Ignore additional colors", .enabled(if: RUNALL))
+  func testIgnoreAdditionalColors() throws {
+    #expect(try ResistorColorDuo.value(for: ["green", "brown", "orange"]) == 51)
+  }
+
+  @Test("Black and brown, one-digit", .enabled(if: RUNALL))
+  func testBlackAndBrownOneDigit() throws {
+    #expect(try ResistorColorDuo.value(for: ["black", "brown"]) == 1)
+  }
+}