Add anagram exercise (#211)

config.json

@@ -511,6 +511,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "anagram",
+        "name": "Anagram",
+        "uuid": "ced95ca8-5145-472e-aaf8-a5998883dbe6",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "armstrong-numbers",
         "name": "Armstrong Numbers",

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

@@ -0,0 +1,13 @@
+# Instructions
+
+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"`.
+
+Given a target word and a set of candidate words, this exercise requests the anagram set: the subset of the candidates that are anagrams of the target.
+
+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/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "anagram.v"
+    ],
+    "test": [
+      "run_test.v"
+    ],
+    "example": [
+      ".meta/example.v"
+    ]
+  },
+  "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/example.v

@@ -0,0 +1,18 @@
+module main
+
+fn find_anagrams(subject string, candidates []string) []string {
+	mut result := []string{cap: candidates.len}
+	mut subject_runes := subject.to_lower().runes()
+	subject_runes.sort()
+	for candidate in candidates {
+		if candidate.to_lower() == subject.to_lower() {
+			continue
+		}
+		mut candidate_runes := candidate.to_lower().runes()
+		candidate_runes.sort()
+		if candidate_runes == subject_runes {
+			result << candidate
+		}
+	}
+	return result
+}

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

@@ -0,0 +1,80 @@
+# This is an auto-generated file. Regular comments will be removed when this
+# file is regenerated. Regenerating will not touch any manually added keys,
+# so comments can be added in 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"
+include = false
+
+[fd3509e5-e3ba-409d-ac3d-a9ac84d13296]
+description = "different characters may have the same bytes"

exercises/practice/anagram/anagram.v

@@ -0,0 +1,4 @@
+module main
+
+fn find_anagrams(subject string, candidates []string) []string {
+}

exercises/practice/anagram/run_test.v

@@ -0,0 +1,103 @@
+module main
+
+fn test_no_matches() {
+	candidates := ['hello', 'world', 'zombies', 'pants']
+	expected := []string{}
+	assert find_anagrams('diaper', candidates) == expected
+}
+
+fn test_detects_two_anagrams() {
+	candidates := ['lemons', 'cherry', 'melons']
+	expected := ['lemons', 'melons']
+	assert find_anagrams('solemn', candidates) == expected
+}
+
+fn test_does_not_detect_anagram_subsets() {
+	candidates := ['dog', 'goody']
+	expected := []string{}
+	assert find_anagrams('good', candidates) == expected
+}
+
+fn test_detects_anagram() {
+	candidates := ['enlists', 'google', 'inlets', 'banana']
+	expected := ['inlets']
+	assert find_anagrams('listen', candidates) == expected
+}
+
+fn test_detects_three_anagrams() {
+	candidates := ['gallery', 'ballerina', 'regally', 'clergy', 'largely', 'leading']
+	expected := ['gallery', 'regally', 'largely']
+	assert find_anagrams('allergy', candidates) == expected
+}
+
+fn test_detects_multiple_anagrams_with_different_case() {
+	candidates := ['Eons', 'ONES']
+	expected := ['Eons', 'ONES']
+	assert find_anagrams('nose', candidates) == expected
+}
+
+fn test_does_not_detect_non_anagrams_with_identical_checksum() {
+	candidates := ['last']
+	expected := []string{}
+	assert find_anagrams('mass', candidates) == expected
+}
+
+fn test_detects_anagrams_case_insensitively() {
+	candidates := ['cashregister', 'Carthorse', 'radishes']
+	expected := ['Carthorse']
+	assert find_anagrams('Orchestra', candidates) == expected
+}
+
+fn test_detects_anagrams_using_case_insensitive_subject() {
+	candidates := ['cashregister', 'carthorse', 'radishes']
+	expected := ['carthorse']
+	assert find_anagrams('Orchestra', candidates) == expected
+}
+
+fn test_detects_anagrams_using_case_insensitive_possible_matches() {
+	candidates := ['cashregister', 'Carthorse', 'radishes']
+	expected := ['Carthorse']
+	assert find_anagrams('orchestra', candidates) == expected
+}
+
+fn test_does_not_detect_an_anagram_if_the_original_word_is_repeated() {
+	candidates := ['goGoGO']
+	expected := []string{}
+	assert find_anagrams('go', candidates) == expected
+}
+
+fn test_anagrams_must_use_all_letters_exactly_once() {
+	candidates := ['patter']
+	expected := []string{}
+	assert find_anagrams('tapper', candidates) == expected
+}
+
+fn test_words_are_not_anagrams_of_themselves() {
+	candidates := ['BANANA']
+	expected := []string{}
+	assert find_anagrams('BANANA', candidates) == expected
+}
+
+fn test_words_are_not_anagrams_of_themselves_even_if_letter_case_is_partially_different() {
+	candidates := ['Banana']
+	expected := []string{}
+	assert find_anagrams('BANANA', candidates) == expected
+}
+
+fn test_words_are_not_anagrams_of_themselves_even_if_letter_case_is_completely_different() {
+	candidates := ['banana']
+	expected := []string{}
+	assert find_anagrams('BANANA', candidates) == expected
+}
+
+fn test_words_other_than_themselves_can_be_anagrams() {
+	candidates := ['LISTEN', 'Silent']
+	expected := ['Silent']
+	assert find_anagrams('LISTEN', candidates) == expected
+}
+
+fn test_different_characters_may_have_the_same_bytes() {
+	candidates := ['€a']
+	expected := []string{}
+	assert find_anagrams('a⬂', candidates) == expected
+}