Add prism (#376)

* Add `prism`

* Test removing `max` call

* Don't square dist twice

* Manually format to 80 char width

* Some additional manual formatting

---------

Co-authored-by: BNAndras <bnandras@example.com>

Author: BNAndras

config.json

@@ -790,6 +790,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "prism",
+        "name": "Prism",
+        "uuid": "4a8f6569-71cc-437d-9bda-e297e275f4f9",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "relative-distance",
         "name": "Relative Distance",

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

@@ -0,0 +1,36 @@
+# 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": 3, "x": 30, "y": 10, "angle": 45 },
+    { "id": 1, "x": 10, "y": 10, "angle": -90 },
+    { "id": 2, "x": 10, "y": 0, "angle": 90 },
+    { "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.

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/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "prism.vim"
+    ],
+    "test": [
+      "prism.vader"
+    ],
+    "example": [
+      ".meta/example.vim"
+    ]
+  },
+  "blurb": "Calculate the path of a laser through reflective prisms.",
+  "source": "FraSanga",
+  "source_url": "https://github.com/exercism/problem-specifications/pull/2625"
+}

exercises/practice/prism/.meta/example.vim

@@ -0,0 +1,63 @@
+function! FindSequence(prisms, start) abort
+  let l:sequence = []
+  let l:x = a:start.x + 0.0
+  let l:y = a:start.y + 0.0
+  let l:angle = a:start.angle + 0.0
+  let l:pi = acos(-1.0)
+  
+  while 1
+    let l:rad = l:angle * l:pi / 180.0
+    let l:dirX = cos(l:rad)
+    let l:dirY = sin(l:rad)
+    
+    let l:nearest = {}
+    let l:nearestDist = 1.0 / 0.0
+    let l:found = 0
+
+    for l:prism in a:prisms
+      let l:dx = l:prism.x - l:x
+      let l:dy = l:prism.y - l:y
+
+      " how far along the ray is the prism?
+      let l:dist = l:dx * l:dirX + l:dy * l:dirY
+      
+      " ignore prisms behind us
+      if l:dist <= 1.0e-6
+        continue
+      endif
+
+      " how far off center is the prism?  
+      let l:crossX = l:dx - l:dist * l:dirX
+      let l:crossY = l:dy - l:dist * l:dirY
+      let l:crossSq = l:crossX * l:crossX + l:crossY * l:crossY
+      
+      " bail if outside relative tolerance (scale by distance)
+      let l:scale = 1.0
+      let l:dist_sq = l:dist * l:dist
+      if l:dist_sq > 1.0
+        let l:scale = l:dist_sq
+      endif
+      if l:crossSq >= 1.0e-6 * l:scale
+        continue
+      endif
+      
+      if l:dist < l:nearestDist
+        let l:nearestDist = l:dist
+        let l:nearest = l:prism
+        let l:found = 1
+      endif
+    endfor
+    
+    if !l:found
+      break
+    endif
+    
+    call add(l:sequence, l:nearest.id)
+    let l:x = l:nearest.x
+    let l:y = l:nearest.y
+    let l:angle = fmod(l:angle + l:nearest.angle, 360.0)
+    
+  endwhile
+
+  return {'sequence': l:sequence}
+endfunction

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"