Add parallel-letter-frequency exercise

config.json

@@ -490,6 +490,14 @@
         "prerequisites": [],
         "difficulty": 6
       },
+      {
+        "slug": "parallel-letter-frequency",
+        "name": "Parallel Letter Frequency",
+        "uuid": "e45c4799-1b12-455e-9972-9804f2414666",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 7
+      },
       {
         "slug": "crypto-square",
         "name": "Crypto Square",

exercises/practice/parallel-letter-frequency/.docs/instructions.md

@@ -0,0 +1,7 @@
+# Instructions
+
+Count the frequency of letters in texts using parallel computation.
+
+Parallelism is about doing things in parallel that can also be done sequentially.
+A common example is counting the frequency of letters.
+Employ parallelism to calculate the total frequency of each letter in a list of texts.

exercises/practice/parallel-letter-frequency/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "parallel-letter-frequency.ua"
+    ],
+    "test": [
+      "tests.ua"
+    ],
+    "example": [
+      ".meta/example.ua"
+    ]
+  },
+  "blurb": "Count the frequency of letters in texts using parallel computation."
+}

exercises/practice/parallel-letter-frequency/.meta/example.ua

@@ -0,0 +1,4 @@
+LetterCount    ← map ⊕⊃⊢⧻ ⊛.¯▽±.⌵
+ParallelCounts ← wait≡spawn⍚LetterCount
+Merge          ← map ⟜(≡(/◇+⍚(⬚0get:):))⊙¤⊸(⍆◴/◇⊂⍚(⊙◌°map))
+Frequencies    ← Merge ParallelCounts

exercises/practice/parallel-letter-frequency/.meta/tests.toml

@@ -0,0 +1,50 @@
+# 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.
+
+[c054d642-c1fa-4234-8007-9339f2337886]
+description = "no texts"
+
+[818031be-49dc-4675-b2f9-c4047f638a2a]
+description = "one text with one letter"
+
+[c0b81d1b-940d-4cea-9f49-8445c69c17ae]
+description = "one text with multiple letters"
+
+[708ff1e0-f14a-43fd-adb5-e76750dcf108]
+description = "two texts with one letter"
+
+[1b5c28bb-4619-4c9d-8db9-a4bb9c3bdca0]
+description = "two texts with multiple letters"
+
+[6366e2b8-b84c-4334-a047-03a00a656d63]
+description = "ignore letter casing"
+
+[92ebcbb0-9181-4421-a784-f6f5aa79f75b]
+description = "ignore whitespace"
+
+[bc5f4203-00ce-4acc-a5fa-f7b865376fd9]
+description = "ignore punctuation"
+
+[68032b8b-346b-4389-a380-e397618f6831]
+description = "ignore numbers"
+
+[aa9f97ac-3961-4af1-88e7-6efed1bfddfd]
+description = "Unicode letters"
+include = false
+
+[7b1da046-701b-41fc-813e-dcfb5ee51813]
+description = "combination of lower- and uppercase letters, punctuation and white space"
+
+[4727f020-df62-4dcf-99b2-a6e58319cb4f]
+description = "large texts"
+
+[adf8e57b-8e54-4483-b6b8-8b32c115884c]
+description = "many small texts"

exercises/practice/parallel-letter-frequency/parallel-letter-frequency.ua

@@ -0,0 +1,3 @@
+# Count the frequency of letters in texts using parallel computation.
+# Frequencies ? Texts
+Frequencies ← |1 ⊙(⍤"Please implement Frequencies" 0)

exercises/practice/parallel-letter-frequency/tests.ua

@@ -0,0 +1,37 @@
+~ "parallel-letter-frequency.ua" ~ Frequencies
+
+# no texts
+⍤⤙≍ 0 ⧻ Frequencies {}
+
+# one text with one letter
+⍤⤙≍ map "a" [1] Frequencies {"a"}
+
+# one text with multiple letters
+⍤⤙≍ map "bcd" [2 3 1] Frequencies {"bbcccd"}
+
+# two texts with one letter
+⍤⤙≍ map "ef" [1 1] Frequencies {"e" "f"}
+
+# two texts with multiple letters
+⍤⤙≍ map "ghi" [2 3 1] Frequencies {"ggh" "hhi"}
+
+# ignore letter casing
+⍤⤙≍ map "m" [2] Frequencies {"m" "M"}
+
+# ignore whitespace
+⍤⤙≍ 0 ⧻ Frequencies {"   " "	" "\n\t"}
+
+# ignore punctuation
+⍤⤙≍ 0 ⧻ Frequencies {"!" "?" ";" "," "."}
+
+# ignore numbers
+⍤⤙≍ 0 ⧻ Frequencies {"1" "2" "3" "4" "5" "6" "7" "8" "9"}
+
+# combination of lower- and uppercase letters, punctuation and white space
+Expected ← map "abcdefghiklmnoprstuvwy" [32 4 6 14 37 7 8 29 19 6 12 7 19 22 7 17 16 30 9 2 9 4]
+Texts    ← {"There, peeping among the cloud-wrack above a dark tower high up in the mountains, Sam saw a white star twinkle for a while. The beauty of it smote his heart, as he looked up out of the forsaken land, and hope returned to him. For like a shaft, clear and cold, the thought pierced him that in the end, the shadow was only a small and passing thing: there was light and high beauty forever beyond its reach."}
+⍤⤙≍ Expected Frequencies Texts
+
+# many small texts
+Texts ← {"abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc" "abbccc"}
+⍤⤙≍ map "abc" [50 100 150] Frequencies Texts