[pythagorean-triplet] Implementation

config.json

@@ -571,6 +571,15 @@
         "prerequisites": [],
         "difficulty": 1,
         "topics": []
+      },
+      {
+        "slug": "pythagorean-triplet",
+        "name": "Pythagorean Triplet",
+        "uuid": "7e517674-28b6-4b47-97ee-cf4517402430",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1,
+        "topics": []
       }
     ]
   },

exercises/practice/pythagorean-triplet/.docs/instructions.md

@@ -0,0 +1,23 @@
+# Instructions
+
+A Pythagorean triplet is a set of three natural numbers, {a, b, c}, for which,
+
+```text
+a² + b² = c²
+```
+
+and such that,
+
+```text
+a < b < c
+```
+
+For example,
+
+```text
+3² + 4² = 5².
+```
+
+Given an input integer N, find all Pythagorean triplets for which `a + b + c = N`.
+
+For example, with N = 1000, there is exactly one Pythagorean triplet for which `a + b + c = 1000`: `{200, 375, 425}`.

exercises/practice/pythagorean-triplet/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "habere-et-dispertire"
+  ],
+  "files": {
+    "solution": [
+      "PythagoreanTriplet.rakumod"
+    ],
+    "test": [
+      "pythagorean-triplet.rakutest"
+    ],
+    "example": [
+      ".meta/solutions/PythagoreanTriplet.rakumod"
+    ]
+  },
+  "blurb": "There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product a * b * c.",
+  "source": "Problem 9 at Project Euler",
+  "source_url": "https://projecteuler.net/problem=9"
+}

exercises/practice/pythagorean-triplet/.meta/solutions/PythagoreanTriplet.rakumod

@@ -0,0 +1,15 @@
+unit module PythagoreanTriplet;
+
+sub triplets-sum ($sum) is export {
+    gather for 1 .. $sum
+    -> $a {
+        given 2×$a² + $sum² - 2×$sum×$a, 2×( $sum - $a )
+        -> ( $numerator, $denominator ) {
+            if $numerator %% $denominator {
+                my $c = $numerator / $denominator;
+                my $b = $sum - $a - $c;
+                take [ $a, $b, $c ] if $b > $a;
+            }
+        }
+    }
+}

exercises/practice/pythagorean-triplet/.meta/solutions/pythagorean-triplet.rakutest

@@ -0,0 +1 @@
+../../pythagorean-triplet.rakutest

exercises/practice/pythagorean-triplet/.meta/template-data.yaml

@@ -0,0 +1,31 @@
+properties:
+  tripletsWithSum:
+    test: |-
+      sprintf(q:to/END/, %case<input><n>.raku, %case<expected>.map(*.List).List.raku, %case<description>.raku);
+      cmp-ok(
+          triplets-sum(%s),
+          "~~",
+          %s,
+          %s,
+      );
+      END
+
+unit: module
+example: |-
+  sub triplets-sum ($sum) is export {
+      gather for 1 .. $sum
+      -> $a {
+          given 2×$a² + $sum² - 2×$sum×$a, 2×( $sum - $a )
+          -> ( $numerator, $denominator ) {
+              if $numerator %% $denominator {
+                  my $c = $numerator / $denominator;
+                  my $b = $sum - $a - $c;
+                  take [ $a, $b, $c ] if $b > $a;
+              }
+          }
+      }
+  }
+
+stub: |-
+  sub triplets-sum ($sum) is export {
+  }

exercises/practice/pythagorean-triplet/.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.
+
+[a19de65d-35b8-4480-b1af-371d9541e706]
+description = "triplets whose sum is 12"
+
+[48b21332-0a3d-43b2-9a52-90b2a6e5c9f5]
+description = "triplets whose sum is 108"
+
+[dffc1266-418e-4daa-81af-54c3e95c3bb5]
+description = "triplets whose sum is 1000"
+
+[5f86a2d4-6383-4cce-93a5-e4489e79b186]
+description = "no matching triplets for 1001"
+
+[bf17ba80-1596-409a-bb13-343bdb3b2904]
+description = "returns all matching triplets"
+
+[9d8fb5d5-6c6f-42df-9f95-d3165963ac57]
+description = "several matching triplets"
+
+[f5be5734-8aa0-4bd1-99a2-02adcc4402b4]
+description = "triplets for large number"

exercises/practice/pythagorean-triplet/PythagoreanTriplet.rakumod

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+unit module PythagoreanTriplet;
+
+sub triplets-sum ($sum) is export {
+}

exercises/practice/pythagorean-triplet/pythagorean-triplet.rakutest

@@ -0,0 +1,55 @@
+#!/usr/bin/env raku
+use Test;
+use lib $?FILE.IO.dirname;
+use PythagoreanTriplet;
+
+cmp-ok( # begin: a19de65d-35b8-4480-b1af-371d9541e706
+    triplets-sum(12),
+    "~~",
+    ((3, 4, 5),),
+    "triplets whose sum is 12",
+); # end: a19de65d-35b8-4480-b1af-371d9541e706
+
+cmp-ok( # begin: 48b21332-0a3d-43b2-9a52-90b2a6e5c9f5
+    triplets-sum(108),
+    "~~",
+    ((27, 36, 45),),
+    "triplets whose sum is 108",
+); # end: 48b21332-0a3d-43b2-9a52-90b2a6e5c9f5
+
+cmp-ok( # begin: dffc1266-418e-4daa-81af-54c3e95c3bb5
+    triplets-sum(1000),
+    "~~",
+    ((200, 375, 425),),
+    "triplets whose sum is 1000",
+); # end: dffc1266-418e-4daa-81af-54c3e95c3bb5
+
+cmp-ok( # begin: 5f86a2d4-6383-4cce-93a5-e4489e79b186
+    triplets-sum(1001),
+    "~~",
+    (),
+    "no matching triplets for 1001",
+); # end: 5f86a2d4-6383-4cce-93a5-e4489e79b186
+
+cmp-ok( # begin: bf17ba80-1596-409a-bb13-343bdb3b2904
+    triplets-sum(90),
+    "~~",
+    ((9, 40, 41), (15, 36, 39)),
+    "returns all matching triplets",
+); # end: bf17ba80-1596-409a-bb13-343bdb3b2904
+
+cmp-ok( # begin: 9d8fb5d5-6c6f-42df-9f95-d3165963ac57
+    triplets-sum(840),
+    "~~",
+    ((40, 399, 401), (56, 390, 394), (105, 360, 375), (120, 350, 370), (140, 336, 364), (168, 315, 357), (210, 280, 350), (240, 252, 348)),
+    "several matching triplets",
+); # end: 9d8fb5d5-6c6f-42df-9f95-d3165963ac57
+
+cmp-ok( # begin: f5be5734-8aa0-4bd1-99a2-02adcc4402b4
+    triplets-sum(30000),
+    "~~",
+    ((1200, 14375, 14425), (1875, 14000, 14125), (5000, 12000, 13000), (6000, 11250, 12750), (7500, 10000, 12500)),
+    "triplets for large number",
+); # end: f5be5734-8aa0-4bd1-99a2-02adcc4402b4
+
+done-testing;