add anagram (#247)

config.json

@@ -42,6 +42,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "anagram",
+        "name": "Anagram",
+        "uuid": "689981bc-14fe-49d9-a981-d8fdee0924ae",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "armstrong-numbers",
         "name": "Armstrong Numbers",

exercises/practice/anagram/.docs/instructions.md

@@ -0,0 +1,13 @@
+# Instructions
+
+Your task is to, given a target word and a set of candidate words, to find the subset of the candidates that are anagrams of the target.
+
+An anagram is a rearrangement of letters to form a new word: for example `"owns"` is an anagram of `"snow"`.
+A word is _not_ its own anagram: for example, `"stop"` is not an anagram of `"stop"`.
+
+The target and candidates are words of one or more ASCII alphabetic characters (`A`-`Z` and `a`-`z`).
+Lowercase and uppercase characters are equivalent: for example, `"PoTS"` is an anagram of `"sTOp"`, but `StoP` is not an anagram of `sTOp`.
+The anagram set is the subset of the candidate set that are anagrams of the target (in any order).
+Words in the anagram set should have the same letter case as in the candidate set.
+
+Given the target `"stone"` and candidates `"stone"`, `"tones"`, `"banana"`, `"tons"`, `"notes"`, `"Seton"`, the anagram set is `"tones"`, `"notes"`, `"Seton"`.

exercises/practice/anagram/.docs/introduction.md

@@ -0,0 +1,12 @@
+# Introduction
+
+At a garage sale, you find a lovely vintage typewriter at a bargain price!
+Excitedly, you rush home, insert a sheet of paper, and start typing away.
+However, your excitement wanes when you examine the output: all words are garbled!
+For example, it prints "stop" instead of "post" and "least" instead of "stale."
+Carefully, you try again, but now it prints "spot" and "slate."
+After some experimentation, you find there is a random delay before each letter is printed, which messes up the order.
+You now understand why they sold it for so little money!
+
+You realize this quirk allows you to generate anagrams, which are words formed by rearranging the letters of another word.
+Pleased with your finding, you spend the rest of the day generating hundreds of anagrams.

exercises/practice/anagram/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "source/anagram.d"
+    ],
+    "test": [
+      "source/anagram.d"
+    ],
+    "example": [
+      "example/anagram.d"
+    ]
+  },
+  "blurb": "Given a word and a list of possible anagrams, select the correct sublist.",
+  "source": "Inspired by the Extreme Startup game",
+  "source_url": "https://github.com/rchatley/extreme_startup"
+}

exercises/practice/anagram/.meta/tests.toml

@@ -0,0 +1,88 @@
+# 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.
+
+[dd40c4d2-3c8b-44e5-992a-f42b393ec373]
+description = "no matches"
+
+[b3cca662-f50a-489e-ae10-ab8290a09bdc]
+description = "detects two anagrams"
+include = false
+
+[03eb9bbe-8906-4ea0-84fa-ffe711b52c8b]
+description = "detects two anagrams"
+reimplements = "b3cca662-f50a-489e-ae10-ab8290a09bdc"
+
+[a27558ee-9ba0-4552-96b1-ecf665b06556]
+description = "does not detect anagram subsets"
+
+[64cd4584-fc15-4781-b633-3d814c4941a4]
+description = "detects anagram"
+
+[99c91beb-838f-4ccd-b123-935139917283]
+description = "detects three anagrams"
+
+[78487770-e258-4e1f-a646-8ece10950d90]
+description = "detects multiple anagrams with different case"
+
+[1d0ab8aa-362f-49b7-9902-3d0c668d557b]
+description = "does not detect non-anagrams with identical checksum"
+
+[9e632c0b-c0b1-4804-8cc1-e295dea6d8a8]
+description = "detects anagrams case-insensitively"
+
+[b248e49f-0905-48d2-9c8d-bd02d8c3e392]
+description = "detects anagrams using case-insensitive subject"
+
+[f367325c-78ec-411c-be76-e79047f4bd54]
+description = "detects anagrams using case-insensitive possible matches"
+
+[7cc195ad-e3c7-44ee-9fd2-d3c344806a2c]
+description = "does not detect an anagram if the original word is repeated"
+include = false
+
+[630abb71-a94e-4715-8395-179ec1df9f91]
+description = "does not detect an anagram if the original word is repeated"
+reimplements = "7cc195ad-e3c7-44ee-9fd2-d3c344806a2c"
+
+[9878a1c9-d6ea-4235-ae51-3ea2befd6842]
+description = "anagrams must use all letters exactly once"
+
+[85757361-4535-45fd-ac0e-3810d40debc1]
+description = "words are not anagrams of themselves (case-insensitive)"
+include = false
+
+[68934ed0-010b-4ef9-857a-20c9012d1ebf]
+description = "words are not anagrams of themselves"
+reimplements = "85757361-4535-45fd-ac0e-3810d40debc1"
+
+[589384f3-4c8a-4e7d-9edc-51c3e5f0c90e]
+description = "words are not anagrams of themselves even if letter case is partially different"
+reimplements = "85757361-4535-45fd-ac0e-3810d40debc1"
+
+[ba53e423-7e02-41ee-9ae2-71f91e6d18e6]
+description = "words are not anagrams of themselves even if letter case is completely different"
+reimplements = "85757361-4535-45fd-ac0e-3810d40debc1"
+
+[a0705568-628c-4b55-9798-82e4acde51ca]
+description = "words other than themselves can be anagrams"
+include = false
+
+[33d3f67e-fbb9-49d3-a90e-0beb00861da7]
+description = "words other than themselves can be anagrams"
+reimplements = "a0705568-628c-4b55-9798-82e4acde51ca"
+
+[a6854f66-eec1-4afd-a137-62ef2870c051]
+description = "handles case of greek letters"
+
+[fd3509e5-e3ba-409d-ac3d-a9ac84d13296]
+description = "different characters may have the same bytes"
+include = false
+

exercises/practice/anagram/dub.sdl

@@ -0,0 +1,2 @@
+name "anagram"
+buildRequirements "disallowDeprecations"

exercises/practice/anagram/example/anagram.d

@@ -0,0 +1,24 @@
+import std.array;
+import std.string;
+import std.algorithm;
+
+pure string[] findAnagrams(immutable string subject, immutable string[] candidates)
+{
+    string[] results = [];
+
+    string loweredSubject = subject.toLower();
+    auto subjectLetters = loweredSubject.split("").sort();
+
+    foreach (candidate; candidates)
+    {
+        string loweredCandidate = candidate.toLower();
+        auto candidateLetters = loweredCandidate.split("").sort();
+
+        if (subjectLetters == candidateLetters && loweredSubject != loweredCandidate)
+        {
+            results ~= candidate;
+        }
+    }
+    return results;
+}
+

exercises/practice/anagram/source/anagram.d

@@ -0,0 +1,186 @@
+module anagram;
+
+pure string[] findAnagrams(immutable string subject, immutable string[] candidates)
+{
+    // implement this function
+}
+
+unittest
+{
+    immutable int allTestsEnabled = 0;
+
+    // no matches
+    {
+        immutable string subject = "diaper";
+        immutable string[] candidates = ["hello", "world", "zombies", "pants"];
+        string[] actual = findAnagrams(subject, candidates);
+        string[] expected = [];
+
+        assert(actual == expected);
+    }
+
+    static if (allTestsEnabled)
+    {
+
+        // detects two anagrams
+        {
+            immutable string subject = "solemn";
+            immutable string[] candidates = ["lemons", "cherry", "melons"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["lemons", "melons"];
+
+            assert(actual == expected);
+        }
+
+        // does not detect anagram subsets
+        {
+            immutable string subject = "good";
+            immutable string[] candidates = ["dog", "goody"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = [];
+
+            assert(actual == expected);
+        }
+
+        // detects anagram
+        {
+            immutable string subject = "listen";
+            immutable string[] candidates = ["enlists", "google", "inlets", "banana"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["inlets"];
+
+            assert(actual == expected);
+        }
+
+        // detects three anagrams
+        {
+            immutable string subject = "allergy";
+            immutable string[] candidates = ["gallery", "ballerina", "regally", "clergy", "largely", "leading"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["gallery", "regally", "largely"];
+
+            assert(actual == expected);
+        }
+
+        // detects multiple anagrams with different case
+        {
+            immutable string subject = "nose";
+            immutable string[] candidates = ["Eons", "ONES"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["Eons", "ONES"];
+
+            assert(actual == expected);
+        }
+
+        // does not detect non-anagrams with identical checksum
+        {
+            immutable string subject = "mass";
+            immutable string[] candidates = ["last"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = [];
+
+            assert(actual == expected);
+        }
+
+        // detects anagrams case-insensitively
+        {
+            immutable string subject = "Orchestra";
+            immutable string[] candidates = ["cashregister", "Carthorse", "radishes"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["Carthorse"];
+
+            assert(actual == expected);
+        }
+
+        // detects anagrams using case-insensitive subject
+        {
+            immutable string subject = "Orchestra";
+            immutable string[] candidates = ["cashregister", "carthorse", "radishes"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["carthorse"];
+
+            assert(actual == expected);
+        }
+
+        // detects anagrams using case-insensitive possible matches
+        {
+            immutable string subject = "orchestra";
+            immutable string[] candidates = ["cashregister", "Carthorse", "radishes"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["Carthorse"];
+
+            assert(actual == expected);
+        }
+
+        // does not detect an anagram if the original word is repeated
+        {
+            immutable string subject = "go";
+            immutable string[] candidates = ["goGoGO"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = [];
+
+            assert(actual == expected);
+        }
+
+        // anagrams must use all letters exactly once
+        {
+            immutable string subject = "tapper";
+            immutable string[] candidates = ["patter"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = [];
+
+            assert(actual == expected);
+        }
+
+        // words are not anagrams of themselves
+        {
+            immutable string subject = "BANANA";
+            immutable string[] candidates = ["BANANA"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = [];
+
+            assert(actual == expected);
+        }
+
+        // words are not anagrams of themselves even if letter case is partially different
+        {
+            immutable string subject = "BANANA";
+            immutable string[] candidates = ["Banana"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = [];
+
+            assert(actual == expected);
+        }
+
+        // words are not anagrams of themselves even if letter case is completely different
+        {
+            immutable string subject = "BANANA";
+            immutable string[] candidates = ["banana"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = [];
+
+            assert(actual == expected);
+        }
+
+        // words other than themselves can be anagrams
+        {
+            immutable string subject = "LISTEN";
+            immutable string[] candidates = ["Listen", "Silent", "LISTEN"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["Silent"];
+
+            assert(actual == expected);
+        }
+
+        // handles case of greek letters
+        {
+            immutable string subject = "ΑΒΓ";
+            immutable string[] candidates = ["ΒΓΑ", "ΒΓΔ", "γβα", "αβγ"];
+            string[] actual = findAnagrams(subject, candidates);
+            string[] expected = ["ΒΓΑ", "γβα"];
+
+            assert(actual == expected);
+        }
+    }
+}
+