Add zebra-puzzle exercise

config.json

@@ -1833,6 +1833,18 @@
           "recursion"
         ],
         "difficulty": 4
+      },
+      {
+        "slug": "zebra-puzzle",
+        "name": "Zebra Puzzle",
+        "uuid": "82a312b6-5d71-4119-b3b0-211d572c17c8",
+        "practices": [
+          "results"
+        ],
+        "prerequisites": [
+          "recursion"
+        ],
+        "difficulty": 9
       }
     ]
   },

exercises/practice/zebra-puzzle/.docs/instructions.md

@@ -0,0 +1,32 @@
+# Instructions
+
+Your task is to solve the Zebra Puzzle to find the answer to these two questions:
+
+- Which of the residents drinks water?
+- Who owns the zebra?
+
+## Puzzle
+
+The following 15 statements are all known to be true:
+
+1. There are five houses.
+2. The Englishman lives in the red house.
+3. The Spaniard owns the dog.
+4. Coffee is drunk in the green house.
+5. The Ukrainian drinks tea.
+6. The green house is immediately to the right of the ivory house.
+7. The Old Gold smoker owns snails.
+8. Kools are smoked in the yellow house.
+9. Milk is drunk in the middle house.
+10. The Norwegian lives in the first house.
+11. The man who smokes Chesterfields lives in the house next to the man with the fox.
+12. Kools are smoked in the house next to the house where the horse is kept.
+13. The Lucky Strike smoker drinks orange juice.
+14. The Japanese smokes Parliaments.
+15. The Norwegian lives next to the blue house.
+
+Additionally, each of the five houses is painted a different color, and their inhabitants are of different national extractions, own different pets, drink different beverages and smoke different brands of cigarettes.
+
+~~~~exercism/note
+There are 24 billion (5!⁵ = 24,883,200,000) possible solutions, so try ruling out as many solutions as possible.
+~~~~

exercises/practice/zebra-puzzle/.docs/introduction.md

@@ -0,0 +1,15 @@
+# Introduction
+
+The Zebra Puzzle is a famous logic puzzle in which there are five houses, each painted a different color.
+The houses have different inhabitants, who have different nationalities, own different pets, drink different beverages and smoke different brands of cigarettes.
+
+To help you solve the puzzle, you're given 15 statements describing the solution.
+However, only by combining the information in _all_ statements will you be able to find the solution to the puzzle.
+
+~~~~exercism/note
+The Zebra Puzzle is a [Constraint satisfaction problem (CSP)][constraint-satisfaction-problem].
+In such a problem, you have a set of possible values and a set of constraints that limit which values are valid.
+Another well-known CSP is Sudoku.
+
+[constraint-satisfaction-problem]: https://en.wikipedia.org/wiki/Constraint_satisfaction_problem
+~~~~

exercises/practice/zebra-puzzle/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": [],
+  "files": {
+    "solution": [
+      "src/zebra_puzzle.gleam"
+    ],
+    "test": [
+      "test/zebra_puzzle_test.gleam"
+    ],
+    "example": [
+      ".meta/example.gleam"
+    ]
+  },
+  "blurb": "Solve the zebra puzzle.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Zebra_Puzzle"
+}

exercises/practice/zebra-puzzle/.meta/example.gleam

@@ -0,0 +1,254 @@
+import gleam/dict.{type Dict}
+import gleam/list
+import gleam/result
+
+pub fn water_drinker() -> Result(String, Nil) {
+  solve()
+  |> result.map(fn(solution) { solution.water_drinker })
+}
+
+pub fn zebra_owner() -> Result(String, Nil) {
+  solve()
+  |> result.map(fn(solution) { solution.zebra_owner })
+}
+
+type Solution {
+  Solution(water_drinker: String, zebra_owner: String)
+}
+
+type Parameters =
+  Dict(String, Int)
+
+type Nationalities =
+  Dict(Int, String)
+
+fn solve() -> Result(Solution, Nil) {
+  solve_for_colour(
+    houses()
+      |> list.permutations(),
+    dict.new(),
+  )
+}
+
+fn houses() {
+  // clue 1
+  [1, 2, 3, 4, 5]
+}
+
+fn right_of(a: Int, b: Int) -> Bool {
+  a == b + 1
+}
+
+fn next_to(a: Int, b: Int) -> Bool {
+  right_of(a, b) || right_of(b, a)
+}
+
+fn first() {
+  1
+}
+
+fn middle() {
+  3
+}
+
+fn solve_for_colour(
+  permutations: List(List(Int)),
+  parameters: Parameters,
+) -> Result(Solution, Nil) {
+  case permutations {
+    [] -> Error(Nil)
+    [perm, ..rest] -> {
+      let assert [red, green, ivory, yellow, blue] = perm
+
+      // clue 6
+      case right_of(green, ivory) {
+        False -> solve_for_colour(rest, parameters)
+        True -> {
+          let parameters =
+            parameters
+            |> dict.insert("red", red)
+            |> dict.insert("blue", blue)
+            |> dict.insert("green", green)
+            |> dict.insert("ivory", ivory)
+            |> dict.insert("yellow", yellow)
+          case
+            solve_for_nationalities(
+              houses()
+                |> list.permutations(),
+              parameters,
+            )
+          {
+            Error(Nil) -> solve_for_colour(rest, parameters)
+            Ok(result) -> Ok(result)
+          }
+        }
+      }
+    }
+  }
+}
+
+fn solve_for_nationalities(
+  permutations: List(List(Int)),
+  parameters: Parameters,
+) -> Result(Solution, Nil) {
+  case permutations {
+    [] -> Error(Nil)
+    [perm, ..rest] -> {
+      let assert [english, spanish, ukranian, norwegian, japanese] = perm
+      let assert Ok(red) = dict.get(parameters, "red")
+      let assert Ok(blue) = dict.get(parameters, "blue")
+
+      // clues: 2, 10, 15
+      case english == red && norwegian == first() && next_to(norwegian, blue) {
+        False -> solve_for_nationalities(rest, parameters)
+        True -> {
+          let parameters =
+            parameters
+            |> dict.insert("english", english)
+            |> dict.insert("spanish", spanish)
+            |> dict.insert("ukranian", ukranian)
+            |> dict.insert("japanese", japanese)
+            |> dict.insert("norwegian", norwegian)
+          let nationalities =
+            dict.from_list([
+              #(english, "EnglishMan"),
+              #(spanish, "Spaniard"),
+              #(ukranian, "Ukranian"),
+              #(japanese, "Japanese"),
+              #(norwegian, "Norwegian"),
+            ])
+          case
+            solve_for_beverages(
+              houses()
+                |> list.permutations(),
+              parameters,
+              nationalities,
+            )
+          {
+            Error(Nil) -> solve_for_nationalities(rest, parameters)
+            Ok(result) -> Ok(result)
+          }
+        }
+      }
+    }
+  }
+}
+
+fn solve_for_beverages(
+  permutations: List(List(Int)),
+  parameters: Parameters,
+  nationalities: Nationalities,
+) -> Result(Solution, Nil) {
+  case permutations {
+    [] -> Error(Nil)
+    [perm, ..rest] -> {
+      let assert [coffee, tea, milk, orange_juice, water] = perm
+      let assert Ok(green) = dict.get(parameters, "green")
+      let assert Ok(ukranian) = dict.get(parameters, "ukranian")
+
+      // clues: 4, 5, 9
+      case coffee == green && tea == ukranian && milk == middle() {
+        False -> solve_for_beverages(rest, parameters, nationalities)
+        True -> {
+          let parameters =
+            parameters
+            |> dict.insert("tea", tea)
+            |> dict.insert("milk", milk)
+            |> dict.insert("water", water)
+            |> dict.insert("coffee", coffee)
+            |> dict.insert("orange_juice", orange_juice)
+          case
+            solve_for_cigarettes(
+              houses()
+                |> list.permutations(),
+              parameters,
+              nationalities,
+            )
+          {
+            Error(Nil) -> solve_for_beverages(rest, parameters, nationalities)
+            Ok(result) -> Ok(result)
+          }
+        }
+      }
+    }
+  }
+}
+
+fn solve_for_cigarettes(
+  permutations: List(List(Int)),
+  parameters: Parameters,
+  nationalities: Nationalities,
+) -> Result(Solution, Nil) {
+  case permutations {
+    [] -> Error(Nil)
+    [perm, ..rest] -> {
+      let assert [old_gold, kools, chesterfields, lucky_strike, parliaments] =
+        perm
+      let assert Ok(yellow) = dict.get(parameters, "yellow")
+      let assert Ok(japanese) = dict.get(parameters, "japanese")
+      let assert Ok(orange_juice) = dict.get(parameters, "orange_juice")
+
+      // clues: 8, 13, 14
+      case
+        kools == yellow
+        && lucky_strike == orange_juice
+        && parliaments == japanese
+      {
+        False -> solve_for_cigarettes(rest, parameters, nationalities)
+        True -> {
+          let parameters =
+            parameters
+            |> dict.insert("kools", kools)
+            |> dict.insert("old_gold", old_gold)
+            |> dict.insert("lucky_strike", lucky_strike)
+            |> dict.insert("parliaments", parliaments)
+            |> dict.insert("chesterfields", chesterfields)
+          case
+            solve_for_pets(
+              houses()
+                |> list.permutations(),
+              parameters,
+              nationalities,
+            )
+          {
+            Error(Nil) -> solve_for_cigarettes(rest, parameters, nationalities)
+            Ok(result) -> Ok(result)
+          }
+        }
+      }
+    }
+  }
+}
+
+fn solve_for_pets(
+  permutations: List(List(Int)),
+  parameters: Parameters,
+  nationalities: Nationalities,
+) -> Result(Solution, Nil) {
+  case permutations {
+    [] -> Error(Nil)
+    [perm, ..rest] -> {
+      let assert [dog, snails, fox, horse, zebra] = perm
+      let assert Ok(kools) = dict.get(parameters, "kools")
+      let assert Ok(spanish) = dict.get(parameters, "spanish")
+      let assert Ok(old_gold) = dict.get(parameters, "old_gold")
+      let assert Ok(chesterfields) = dict.get(parameters, "chesterfields")
+
+      // clues: 3, 7, 11, 12
+      case
+        dog == spanish
+        && snails == old_gold
+        && next_to(fox, chesterfields)
+        && next_to(horse, kools)
+      {
+        False -> solve_for_pets(rest, parameters, nationalities)
+        True -> {
+          let assert Ok(water) = dict.get(parameters, "water")
+          let assert Ok(water_owner) = dict.get(nationalities, water)
+          let assert Ok(zebra_owner) = dict.get(nationalities, zebra)
+          Ok(Solution(water_owner, zebra_owner))
+        }
+      }
+    }
+  }
+}

exercises/practice/zebra-puzzle/.meta/tests.toml

@@ -0,0 +1,16 @@
+# 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.
+
+[16efb4e4-8ad7-4d5e-ba96-e5537b66fd42]
+description = "resident who drinks water"
+
+[084d5b8b-24e2-40e6-b008-c800da8cd257]
+description = "resident who owns zebra"

exercises/practice/zebra-puzzle/gleam.toml

@@ -0,0 +1,12 @@
+name = "zebra_puzzle"
+version = "0.1.0"
+
+[dependencies]
+gleam_bitwise = "~> 1.2"
+gleam_otp = "~> 0.7 or ~> 1.0"
+gleam_stdlib = "~> 0.32 or ~> 1.0"
+simplifile = "~> 1.0"
+gleam_erlang = ">= 0.25.0 and < 1.0.0"
+
+[dev-dependencies]
+exercism_test_runner = "~> 1.4"

exercises/practice/zebra-puzzle/manifest.toml

@@ -0,0 +1,27 @@
+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "argv", version = "1.0.1", build_tools = ["gleam"], requirements = [], otp_app = "argv", source = "hex", outer_checksum = "A6E9009E50BBE863EB37D963E4315398D41A3D87D0075480FC244125808F964A" },
+  { name = "exercism_test_runner", version = "1.7.0", build_tools = ["gleam"], requirements = ["argv", "gap", "glance", "gleam_community_ansi", "gleam_erlang", "gleam_json", "gleam_stdlib", "simplifile"], otp_app = "exercism_test_runner", source = "hex", outer_checksum = "2FC1BADB19BEC2AE77BFD2D3A606A014C85412A7B874CAFC4BA8CF04B0B257CD" },
+  { name = "gap", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_community_ansi", "gleam_stdlib"], otp_app = "gap", source = "hex", outer_checksum = "2EE1B0A17E85CF73A0C1D29DA315A2699117A8F549C8E8D89FA8261BE41EDEB1" },
+  { name = "glance", version = "0.8.2", build_tools = ["gleam"], requirements = ["gleam_stdlib", "glexer"], otp_app = "glance", source = "hex", outer_checksum = "ACF09457E8B564AD7A0D823DAFDD326F58263C01ACB0D432A9BEFDEDD1DA8E73" },
+  { name = "gleam_bitwise", version = "1.3.1", build_tools = ["gleam"], requirements = [], otp_app = "gleam_bitwise", source = "hex", outer_checksum = "B36E1D3188D7F594C7FD4F43D0D2CE17561DE896202017548578B16FE1FE9EFC" },
+  { name = "gleam_community_ansi", version = "1.4.0", build_tools = ["gleam"], requirements = ["gleam_community_colour", "gleam_stdlib"], otp_app = "gleam_community_ansi", source = "hex", outer_checksum = "FE79E08BF97009729259B6357EC058315B6FBB916FAD1C2FF9355115FEB0D3A4" },
+  { name = "gleam_community_colour", version = "1.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_community_colour", source = "hex", outer_checksum = "A49A5E3AE8B637A5ACBA80ECB9B1AFE89FD3D5351FF6410A42B84F666D40D7D5" },
+  { name = "gleam_erlang", version = "0.25.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "054D571A7092D2A9727B3E5D183B7507DAB0DA41556EC9133606F09C15497373" },
+  { name = "gleam_json", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "thoas"], otp_app = "gleam_json", source = "hex", outer_checksum = "8B197DD5D578EA6AC2C0D4BDC634C71A5BCA8E7DB5F47091C263ECB411A60DF3" },
+  { name = "gleam_otp", version = "0.10.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "gleam_otp", source = "hex", outer_checksum = "0B04FE915ACECE539B317F9652CAADBBC0F000184D586AAAF2D94C100945D72B" },
+  { name = "gleam_stdlib", version = "0.36.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "C0D14D807FEC6F8A08A7C9EF8DFDE6AE5C10E40E21325B2B29365965D82EB3D4" },
+  { name = "glexer", version = "0.7.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "glexer", source = "hex", outer_checksum = "4484942A465482A0A100936E1E5F12314DB4B5AC0D87575A7B9E9062090B96BE" },
+  { name = "simplifile", version = "1.5.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "simplifile", source = "hex", outer_checksum = "EB9AA8E65E5C1E3E0FDCFC81BC363FD433CB122D7D062750FFDF24DE4AC40116" },
+  { name = "thoas", version = "0.4.1", build_tools = ["rebar3"], requirements = [], otp_app = "thoas", source = "hex", outer_checksum = "4918D50026C073C4AB1388437132C77A6F6F7C8AC43C60C13758CC0ADCE2134E" },
+]
+
+[requirements]
+exercism_test_runner = { version = "~> 1.4" }
+gleam_bitwise = { version = "~> 1.2" }
+gleam_erlang = { version = ">= 0.25.0 and < 1.0.0"}
+gleam_otp = { version = "~> 0.7 or ~> 1.0" }
+gleam_stdlib = { version = "~> 0.32 or ~> 1.0" }
+simplifile = { version = "~> 1.0" }