Add triangle (#287)

config.json

@@ -610,6 +610,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "triangle",
+        "name": "Triangle",
+        "uuid": "e6c705f5-9b34-44a1-9108-d43207bfd97c",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "scrabble-score",
         "name": "Scrabble Score",

exercises/practice/triangle/.docs/instructions.md

@@ -0,0 +1,29 @@
+# Instructions
+
+Determine if a triangle is equilateral, isosceles, or scalene.
+
+An _equilateral_ triangle has all three sides the same length.
+
+An _isosceles_ triangle has at least two sides the same length.
+(It is sometimes specified as having exactly two sides the same length, but for the purposes of this exercise we'll say at least two.)
+
+A _scalene_ triangle has all sides of different lengths.
+
+## Note
+
+For a shape to be a triangle at all, all sides have to be of length > 0, and the sum of the lengths of any two sides must be greater than or equal to the length of the third side.
+
+In equations:
+
+Let `a`, `b`, and `c` be sides of the triangle.
+Then all three of the following expressions must be true:
+
+```text
+a + b ≥ c
+b + c ≥ a
+a + c ≥ b
+```
+
+See [Triangle Inequality][triangle-inequality]
+
+[triangle-inequality]: https://en.wikipedia.org/wiki/Triangle_inequality

exercises/practice/triangle/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "triangle.bal"
+    ],
+    "test": [
+      "tests/triangle_test.bal"
+    ],
+    "example": [
+      ".meta/reference/triangle.bal"
+    ]
+  },
+  "blurb": "Determine if a triangle is equilateral, isosceles, or scalene.",
+  "source": "The Ruby Koans triangle project, parts 1 & 2",
+  "source_url": "https://web.archive.org/web/20220831105330/http://rubykoans.com"
+}

exercises/practice/triangle/.meta/reference/triangle.bal

@@ -0,0 +1,46 @@
+enum TriangleType {
+    EQUILATERAL,
+    ISOSCELES,
+    SCALENE
+}
+
+# Determines the type of triangle based on the sides
+# 
+# + sides - The sides of the triangle
+# + t - The type of triangle
+# + return - Whether the sides form the triangle type
+function kind(float[]|int[] sides, TriangleType t) returns boolean {
+    if !valid(sides) {
+        return false;
+    }
+
+    match t {
+        EQUILATERAL => {
+            return sides[0] == sides[1] && sides[1] == sides[2];
+        }
+        ISOSCELES => {
+            return sides[0] == sides[1] || sides[1] == sides[2] || sides[0] == sides[2];
+        }
+        SCALENE => {
+            return sides[0] != sides[1] && sides[1] != sides[2] && sides[0] != sides[2];
+        }
+    }
+
+    return false;
+}
+
+# Determines if the sides form a valid triangle
+# 
+# + sides - The sides of the triangle
+# + return - Whether the sides form a valid triangle
+function valid(int[]|float[] sides) returns boolean {
+    if sides is float[] {
+        float[] sorted = sides.sort();
+        return sorted.every(function(float num) returns boolean => num > 0.0) && sorted[0] + sorted[1] > sorted[2];
+    } else if sides is int[]{
+        int[] sorted = sides.sort();
+        return sorted.every(function(int num) returns boolean => num > 0) && sorted[0] + sorted[1] > sorted[2];
+    }
+
+    return false;
+}

exercises/practice/triangle/.meta/tests.toml

@@ -0,0 +1,73 @@
+# 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.
+
+[8b2c43ac-7257-43f9-b552-7631a91988af]
+description = "equilateral triangle -> all sides are equal"
+
+[33eb6f87-0498-4ccf-9573-7f8c3ce92b7b]
+description = "equilateral triangle -> any side is unequal"
+
+[c6585b7d-a8c0-4ad8-8a34-e21d36f7ad87]
+description = "equilateral triangle -> no sides are equal"
+
+[16e8ceb0-eadb-46d1-b892-c50327479251]
+description = "equilateral triangle -> all zero sides is not a triangle"
+
+[3022f537-b8e5-4cc1-8f12-fd775827a00c]
+description = "equilateral triangle -> sides may be floats"
+
+[cbc612dc-d75a-4c1c-87fc-e2d5edd70b71]
+description = "isosceles triangle -> last two sides are equal"
+
+[e388ce93-f25e-4daf-b977-4b7ede992217]
+description = "isosceles triangle -> first two sides are equal"
+
+[d2080b79-4523-4c3f-9d42-2da6e81ab30f]
+description = "isosceles triangle -> first and last sides are equal"
+
+[8d71e185-2bd7-4841-b7e1-71689a5491d8]
+description = "isosceles triangle -> equilateral triangles are also isosceles"
+
+[840ed5f8-366f-43c5-ac69-8f05e6f10bbb]
+description = "isosceles triangle -> no sides are equal"
+
+[2eba0cfb-6c65-4c40-8146-30b608905eae]
+description = "isosceles triangle -> first triangle inequality violation"
+
+[278469cb-ac6b-41f0-81d4-66d9b828f8ac]
+description = "isosceles triangle -> second triangle inequality violation"
+
+[90efb0c7-72bb-4514-b320-3a3892e278ff]
+description = "isosceles triangle -> third triangle inequality violation"
+
+[adb4ee20-532f-43dc-8d31-e9271b7ef2bc]
+description = "isosceles triangle -> sides may be floats"
+
+[e8b5f09c-ec2e-47c1-abec-f35095733afb]
+description = "scalene triangle -> no sides are equal"
+
+[2510001f-b44d-4d18-9872-2303e7977dc1]
+description = "scalene triangle -> all sides are equal"
+
+[c6e15a92-90d9-4fb3-90a2-eef64f8d3e1e]
+description = "scalene triangle -> first and second sides are equal"
+
+[3da23a91-a166-419a-9abf-baf4868fd985]
+description = "scalene triangle -> first and third sides are equal"
+
+[b6a75d98-1fef-4c42-8e9a-9db854ba0a4d]
+description = "scalene triangle -> second and third sides are equal"
+
+[70ad5154-0033-48b7-af2c-b8d739cd9fdc]
+description = "scalene triangle -> may not violate triangle inequality"
+
+[26d9d59d-f8f1-40d3-ad58-ae4d54123d7d]
+description = "scalene triangle -> sides may be floats"

exercises/practice/triangle/Ballerina.toml

@@ -0,0 +1,5 @@
+[package]
+org = "ballerina_exercism"
+name = "triangle"
+version = "0.1.0"
+distribution = "2201.5.0"

exercises/practice/triangle/Dependencies.toml

@@ -0,0 +1,38 @@
+# AUTO-GENERATED FILE. DO NOT MODIFY.
+
+# This file is auto-generated by Ballerina for managing dependency versions.
+# It should not be modified by hand.
+
+[ballerina]
+dependencies-toml-version = "2"
+distribution-version = "2201.5.0"
+
+[[package]]
+org = "ballerina"
+name = "jballerina.java"
+version = "0.0.0"
+scope = "testOnly"
+
+[[package]]
+org = "ballerina"
+name = "test"
+version = "0.0.0"
+scope = "testOnly"
+dependencies = [
+	{org = "ballerina", name = "jballerina.java"}
+]
+modules = [
+	{org = "ballerina", packageName = "test", moduleName = "test"}
+]
+
+[[package]]
+org = "ballerina_exercism"
+name = "triangle"
+version = "0.1.0"
+dependencies = [
+	{org = "ballerina", name = "test"}
+]
+modules = [
+	{org = "ballerina_exercism", packageName = "triangle", moduleName = "triangle"}
+]
+