add prism

config.json

@@ -2148,6 +2148,21 @@
         ],
         "difficulty": 4
       },
+      {
+        "slug": "prism",
+        "name": "Prism",
+        "uuid": "c52d3d36-4852-48ff-b97c-0b030a5b365d",
+        "practices": [
+          "arrays",
+          "floating-point-numbers",
+          "while-loops"
+        ],
+        "prerequisites": [
+          "arrays",
+          "floating-point-numbers"
+        ],
+        "difficulty": 4
+      },
       {
         "slug": "twelve-days",
         "name": "Twelve Days",

exercises/Exercises.slnx

@@ -129,6 +129,7 @@
     <Project Path="practice/pov/Pov.csproj" />
     <Project Path="practice/prime-factors/PrimeFactors.csproj" />
     <Project Path="practice/protein-translation/ProteinTranslation.csproj" />
+    <Project Path="practice/prism/Prism.csproj" />
     <Project Path="practice/proverb/Proverb.csproj" />
     <Project Path="practice/pythagorean-triplet/PythagoreanTriplet.csproj" />
     <Project Path="practice/queen-attack/QueenAttack.csproj" />

exercises/practice/prism/.docs/instructions.md

@@ -0,0 +1,38 @@
+# Instructions
+
+Before activating the laser array, you must predict the exact order in which crystals will be hit, identified by their sample IDs.
+
+## Example Test Case
+
+Consider this crystal array configuration:
+
+```json
+{
+  "start": { "x": 0, "y": 0, "angle": 0 },
+  "prisms": [
+    { "id": 1, "x": 10, "y": 10, "angle": -90 },
+    { "id": 2, "x": 10, "y": 0, "angle": 90 },
+    { "id": 3, "x": 30, "y": 10, "angle": 45 },
+    { "id": 4, "x": 20, "y": 0, "angle": 0 }
+  ]
+}
+```
+
+## What's Happening
+
+The laser starts at the origin `(0, 0)` and fires horizontally to the right at angle 0°.
+Here's the step-by-step beam path:
+
+**Step 1**: The beam travels along the x-axis (y = 0) and first encounters **Crystal #2** at position `(10, 0)`.
+This crystal has a refraction angle of 90°, which means it bends the beam perpendicular to its current path.
+The beam, originally traveling at 0°, is now redirected to 90° (straight up).
+
+**Step 2**: The beam now travels vertically upward from position `(10, 0)` and strikes **Crystal #1** at position `(10, 10)`.
+This crystal has a refraction angle of -90°, bending the beam by -90° relative to its current direction.
+The beam was traveling at 90°, so after refraction it's now at 0° (90° + (-90°) = 0°), traveling horizontally to the right again.
+
+**Step 3**: From position `(10, 10)`, the beam travels horizontally and encounters **Crystal #3** at position `(30, 10)`.
+This crystal refracts the beam by 45°, changing its direction to 45°.
+The beam continues into empty space beyond the array.
+
+!["A graph showing the path of a laser beam refracted through three prisms."](https://assets.exercism.org/images/exercises/prism/laser_path-light.svg)

exercises/practice/prism/.docs/introduction.md

@@ -0,0 +1,5 @@
+# Introduction
+
+You're a researcher at **PRISM** (Precariously Redirected Illumination Safety Management), working with a precision laser calibration system that tests experimental crystal prisms.
+These crystals are being developed for next-generation optical computers, and each one has unique refractive properties based on its molecular structure.
+The lab's laser system can damage crystals if they receive unexpected illumination, so precise path prediction is critical.

exercises/practice/prism/.editorconfig

@@ -0,0 +1,141 @@
+###############################
+# Core EditorConfig Options   #
+###############################
+
+; This file is for unifying the coding style for different editors and IDEs.
+; More information at:
+; https://docs.microsoft.com/en-us/visualstudio/ide/editorconfig-code-style-settings-reference?view=vs-2017
+; https://docs.microsoft.com/en-us/visualstudio/ide/create-portable-custom-editor-options?view=vs-2017
+
+root = true
+
+[*]
+indent_style = space
+
+[ProteinTranslation.cs]
+indent_size = 4
+
+###############################
+# .NET Coding Conventions     #
+###############################
+
+# Organize usings
+dotnet_sort_system_directives_first = true
+dotnet_separate_import_directive_groups = true
+
+# this. preferences
+dotnet_style_qualification_for_field = false:suggestion
+dotnet_style_qualification_for_property = false:suggestion
+dotnet_style_qualification_for_method = false:suggestion
+dotnet_style_qualification_for_event = false:suggestion
+
+# Language keywords vs BCL types preferences
+dotnet_style_predefined_type_for_locals_parameters_members = true:suggestion
+dotnet_style_predefined_type_for_member_access = true:suggestion
+
+# Parentheses preferences
+dotnet_style_parentheses_in_arithmetic_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_relational_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_other_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_other_operators = never_if_unnecessary:suggestion
+
+# Modifier preferences
+dotnet_style_require_accessibility_modifiers = always:suggestion
+dotnet_style_readonly_field = true:suggestion
+
+# Expression-level preferences
+dotnet_style_object_initializer = true:suggestion
+dotnet_style_collection_initializer = true:suggestion
+dotnet_style_explicit_tuple_names = true:suggestion
+dotnet_style_prefer_inferred_tuple_names = true:suggestion
+dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion
+dotnet_style_prefer_auto_properties = true:suggestion
+dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion
+dotnet_style_prefer_conditional_expression_over_assignment = true:suggestion
+dotnet_style_prefer_conditional_expression_over_return = true:suggestion
+dotnet_style_coalesce_expression = true:suggestion
+dotnet_style_null_propagation = true:suggestion
+
+###############################
+# Naming Conventions          #
+###############################
+
+# Style Definitions
+dotnet_naming_style.pascal_case_style.capitalization = pascal_case
+
+# Use PascalCase for constant fields
+dotnet_naming_rule.constant_fields_should_be_pascal_case.severity = suggestion
+dotnet_naming_rule.constant_fields_should_be_pascal_case.symbols = constant_fields
+dotnet_naming_rule.constant_fields_should_be_pascal_case.style = pascal_case_style
+dotnet_naming_symbols.constant_fields.applicable_kinds = field
+dotnet_naming_symbols.constant_fields.applicable_accessibilities = *
+dotnet_naming_symbols.constant_fields.required_modifiers = const
+
+###############################
+# C# Code Style Rules         #
+###############################
+
+# var preferences
+csharp_style_var_for_built_in_types = true:none
+csharp_style_var_when_type_is_apparent = true:none
+csharp_style_var_elsewhere = true:none
+
+# Expression-bodied members
+csharp_style_expression_bodied_methods = true:suggestion
+csharp_style_expression_bodied_constructors = true:suggestion
+csharp_style_expression_bodied_operators = true:suggestion
+csharp_style_expression_bodied_properties = true:suggestion
+csharp_style_expression_bodied_indexers = true:suggestion
+csharp_style_expression_bodied_accessors = true:suggestion
+
+# Pattern-matching preferences
+csharp_style_pattern_matching_over_is_with_cast_check = true:suggestion
+csharp_style_pattern_matching_over_as_with_null_check = true:suggestion
+
+# Null-checking preferences
+csharp_style_throw_expression = true:suggestion
+csharp_style_conditional_delegate_call = true:suggestion
+
+# Modifier preferences
+csharp_preferred_modifier_order = public,private,protected,internal,static,extern,new,virtual,abstract,sealed,override,readonly,unsafe,volatile,async:suggestion
+
+# Expression-level preferences
+csharp_prefer_braces = true:none
+csharp_prefer_simple_default_expression = true:suggestion
+csharp_style_deconstructed_variable_declaration = true:suggestion
+csharp_style_pattern_local_over_anonymous_function = true:suggestion
+csharp_style_inlined_variable_declaration = true:suggestion
+
+###############################
+# C# Formatting Rules         #
+###############################
+
+# New line preferences
+csharp_new_line_before_open_brace = all
+csharp_new_line_before_else = true
+csharp_new_line_before_catch = true
+csharp_new_line_before_finally = true
+csharp_new_line_before_members_in_object_initializers = false
+csharp_new_line_before_members_in_anonymous_types = false
+csharp_new_line_between_query_expression_clauses = true
+
+# Indentation preferences
+csharp_indent_case_contents = true
+csharp_indent_switch_labels = true
+csharp_indent_labels = flush_left
+
+# Space preferences
+csharp_space_after_cast = false
+csharp_space_after_keywords_in_control_flow_statements = true
+csharp_space_between_method_declaration_parameter_list_parentheses = false
+csharp_space_between_method_call_parameter_list_parentheses = false
+csharp_space_before_colon_in_inheritance_clause = true
+csharp_space_after_colon_in_inheritance_clause = true
+csharp_space_around_binary_operators = before_and_after
+csharp_space_between_method_declaration_empty_parameter_list_parentheses = false
+csharp_space_between_method_call_name_and_opening_parenthesis = false
+csharp_space_between_method_call_empty_parameter_list_parentheses = false
+
+# Wrapping preferences
+csharp_preserve_single_line_blocks = true
+csharp_preserve_single_line_statements = true

exercises/practice/prism/.meta/Example.cs

@@ -0,0 +1,54 @@
+public static class Prism
+{
+    public readonly record struct LaserInfo(double X, double Y, double Angle);
+
+    public readonly record struct PrismInfo(int Id, double X, double Y, double Angle);
+
+    public static int[] FindSequence(LaserInfo laser, PrismInfo[] prisms)
+    {
+        var x = laser.X;
+        var y = laser.Y;
+        var angle = laser.Angle;
+        List<int> sequence = new();
+
+        while (true)
+        {
+            var rad = double.DegreesToRadians(angle);
+            var dirX = double.Cos(rad);
+            var dirY = double.Sin(rad);
+
+            PrismInfo? nearest = null;
+            var nearestDist = double.PositiveInfinity;
+
+            foreach (var prism in prisms)
+            {
+                var dx = prism.X - x;
+                var dy = prism.Y - y;
+
+                var dist = dx * dirX + dy * dirY;
+                if (dist <= 1e-6)
+                    continue;
+
+                var crossSq = double.Pow(dx - dist * dirX, 2) + double.Pow(dy - dist * dirY, 2);
+                if (crossSq >= 1e-6 * double.Max(1, dist * dist))
+                    continue;
+
+                if (dist < nearestDist)
+                {
+                    nearestDist = dist;
+                    nearest = prism;
+                }
+            }
+
+            if (nearest is not { } hit)
+                break;
+
+            sequence.Add(hit.Id);
+            x = hit.X;
+            y = hit.Y;
+            angle = (angle + hit.Angle) % 360;
+        }
+
+        return sequence.ToArray();
+    }
+}

exercises/practice/prism/.meta/Generator.tpl

@@ -0,0 +1,22 @@
+public class {{ testClass }}
+{
+    {{- for test in tests }}
+    [Fact{{ if !for.first }}(Skip = "Remove this Skip property to run this test"){{ end }}]
+    public void {{ test.testMethod }}()
+    {
+        Prism.LaserInfo laser = new({{ test.input.start.x }}, {{ test.input.start.y }}, {{ test.input.start.angle }});
+        {{- if test.input.prisms.empty? }}
+        Prism.PrismInfo[] prisms = [];
+        {{- else }}
+        Prism.PrismInfo[] prisms =
+        [
+            {{- for p in test.input.prisms }}
+            new({{ p.id }}, {{ p.x }}, {{ p.y }}, {{ p.angle }}){{ if !for.last }},{{ end }}
+            {{- end }}
+        ];
+        {{- end }}
+        int[] expected = [{{ array.join test.expected.sequence ", " }}];
+        Assert.Equal(expected, {{ testedClass }}.{{ test.testedMethod }}(laser, prisms));
+    }
+    {{ end -}}
+}

exercises/practice/prism/.meta/config.json

@@ -0,0 +1,22 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "Prism.cs"
+    ],
+    "test": [
+      "PrismTests.cs"
+    ],
+    "example": [
+      ".meta/Example.cs"
+    ],
+    "invalidator": [
+      "Prism.csproj"
+    ]
+  },
+  "blurb": "Calculate the path of a laser through refractive prisms.",
+  "source": "FraSanga",
+  "source_url": "https://github.com/exercism/problem-specifications/pull/2625"
+}

exercises/practice/prism/.meta/tests.toml

@@ -0,0 +1,52 @@
+# 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.
+
+[ec65d3b3-f7bf-4015-8156-0609c141c4c4]
+description = "zero prisms"
+
+[ec0ca17c-0c5f-44fb-89ba-b76395bdaf1c]
+description = "one prism one hit"
+
+[0db955f2-0a27-4c82-ba67-197bd6202069]
+description = "one prism zero hits"
+
+[8d92485b-ebc0-4ee9-9b88-cdddb16b52da]
+description = "going up zero hits"
+
+[78295b3c-7438-492d-8010-9c63f5c223d7]
+description = "going down zero hits"
+
+[acc723ea-597b-4a50-8d1b-b980fe867d4c]
+description = "going left zero hits"
+
+[3f19b9df-9eaa-4f18-a2db-76132f466d17]
+description = "negative angle"
+
+[96dacffb-d821-4cdf-aed8-f152ce063195]
+description = "large angle"
+
+[513a7caa-957f-4c5d-9820-076842de113c]
+description = "upward refraction two hits"
+
+[d452b7c7-9761-4ea9-81a9-2de1d73eb9ef]
+description = "downward refraction two hits"
+
+[be1a2167-bf4c-4834-acc9-e4d68e1a0203]
+description = "same prism twice"
+
+[df5a60dd-7c7d-4937-ac4f-c832dae79e2e]
+description = "simple path"
+
+[8d9a3cc8-e846-4a3b-a137-4bfc4aa70bd1]
+description = "multiple prisms floating point precision"
+
+[e077fc91-4e4a-46b3-a0f5-0ba00321da56]
+description = "complex path with multiple prisms floating point precision"

exercises/practice/prism/Prism.cs

@@ -0,0 +1,11 @@
+public static class Prism
+{
+    public readonly record struct LaserInfo(double X, double Y, double Angle);
+
+    public readonly record struct PrismInfo(int Id, double X, double Y, double Angle);
+
+    public static int[] FindSequence(LaserInfo laser, PrismInfo[] prisms)
+    {
+        throw new NotImplementedException("You need to implement this method.");
+    }
+}