Add series exercise (#112)

Author: keiravillekode

bin/add-practice-exercise

@@ -71,6 +71,8 @@ fi
 exercise_dir="exercises/practice/${slug}"
 files=$(jq -r --arg dir "${exercise_dir}" '.files | to_entries | map({key: .key, value: (.value | map("'"'"'" + $dir + "/" + . + "'"'"'") | join(" and "))}) | from_entries' "${exercise_dir}/.meta/config.json")
 
+touch "generators/exercises/${slug//-/_}.py"
+
 cat << NEXT_STEPS
 
 Your next steps are:

config.json

@@ -385,6 +385,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "series",
+        "name": "Series",
+        "uuid": "4f4ae55e-e180-47d9-90bf-be104a3f7b31",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "sieve",
         "name": "Sieve",

exercises/practice/series/.docs/instructions.md

@@ -0,0 +1,19 @@
+# Instructions
+
+Given a string of digits, output all the contiguous substrings of length `n` in that string in the order that they appear.
+
+For example, the string "49142" has the following 3-digit series:
+
+- "491"
+- "914"
+- "142"
+
+And the following 4-digit series:
+
+- "4914"
+- "9142"
+
+And if you ask for a 6-digit series from a 5-digit string, you deserve whatever you get.
+
+Note that these series are only required to occupy _adjacent positions_ in the input;
+the digits need not be _numerically consecutive_.

exercises/practice/series/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "series.fut"
+    ],
+    "test": [
+      "test.fut"
+    ],
+    "example": [
+      ".meta/example.fut"
+    ]
+  },
+  "blurb": "Given a string of digits, output all the contiguous substrings of length `n` in that string.",
+  "source": "A subset of the Problem 8 at Project Euler",
+  "source_url": "https://projecteuler.net/problem=8"
+}

exercises/practice/series/.meta/example.fut

@@ -0,0 +1,6 @@
+def slices (series: []u8) (sliceLength: i64): [][]u8 =
+  let seriesLength = length series
+  let n = seriesLength + 1 - sliceLength
+  let slice = \i -> series[i:i + sliceLength] :> [sliceLength]u8
+  in
+    assert (1 <= n && n <= seriesLength) (tabulate n slice)

exercises/practice/series/.meta/tests.toml

@@ -0,0 +1,43 @@
+# 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.
+
+[7ae7a46a-d992-4c2a-9c15-a112d125ebad]
+description = "slices of one from one"
+
+[3143b71d-f6a5-4221-aeae-619f906244d2]
+description = "slices of one from two"
+
+[dbb68ff5-76c5-4ccd-895a-93dbec6d5805]
+description = "slices of two"
+
+[19bbea47-c987-4e11-a7d1-e103442adf86]
+description = "slices of two overlap"
+
+[8e17148d-ba0a-4007-a07f-d7f87015d84c]
+description = "slices can include duplicates"
+
+[bd5b085e-f612-4f81-97a8-6314258278b0]
+description = "slices of a long series"
+
+[6d235d85-46cf-4fae-9955-14b6efef27cd]
+description = "slice length is too large"
+
+[d7957455-346d-4e47-8e4b-87ed1564c6d7]
+description = "slice length is way too large"
+
+[d34004ad-8765-4c09-8ba1-ada8ce776806]
+description = "slice length cannot be zero"
+
+[10ab822d-8410-470a-a85d-23fbeb549e54]
+description = "slice length cannot be negative"
+
+[c7ed0812-0e4b-4bf3-99c4-28cbbfc246a2]
+description = "empty series is invalid"

exercises/practice/series/series.fut

@@ -0,0 +1 @@
+def slices (series: []u8) (sliceLength: i64): [][]u8 = ???

exercises/practice/series/test.fut

@@ -0,0 +1,59 @@
+import "series"
+
+-- slices of one from one
+-- ==
+-- input  { "1" 1 }
+-- output { ["1"] }
+
+-- slices of one from two
+-- ==
+-- input  { "12" 1 }
+-- output { ["1", "2"] }
+
+-- slices of two
+-- ==
+-- input  { "35" 2 }
+-- output { ["35"] }
+
+-- slices of two overlap
+-- ==
+-- input  { "9142" 2 }
+-- output { ["91", "14", "42"] }
+
+-- slices can include duplicates
+-- ==
+-- input  { "777777" 3 }
+-- output { ["777", "777", "777", "777"] }
+
+-- slices of a long series
+-- ==
+-- input  { "918493904243" 5 }
+-- output { ["91849", "18493", "84939", "49390", "93904", "39042", "90424", "04243"] }
+
+-- slice length is too large
+-- ==
+-- input  { "12345" 6 }
+-- error: Error*
+
+-- slice length is way too large
+-- ==
+-- input  { "12345" 42 }
+-- error: Error*
+
+-- slice length cannot be zero
+-- ==
+-- input  { "12345" 0 }
+-- error: Error*
+
+-- slice length cannot be negative
+-- ==
+-- input  { "123" -1 }
+-- error: Error*
+
+-- empty series is invalid
+-- ==
+-- input  { "" 1 }
+-- error: Error*
+
+let main (series: []u8) (sliceLength: i32): [][]u8 =
+  slices series (i64.i32 sliceLength)

generators/exercises/series.py

@@ -0,0 +1,17 @@
+def gen_test_case(prop, description, inp, expected, f):
+    series = inp["series"]
+    sliceLength = inp["sliceLength"]
+
+    f.write(f"-- {description}\n")
+    f.write("-- ==\n")
+    f.write(f'-- input  {{ "{series}" {sliceLength} }}\n')
+    if isinstance(expected, dict):
+        f.write("-- error: Error*\n\n")
+    else:
+        expected = str(expected).replace("'", '"')
+        f.write(f"-- output {{ {expected} }}\n\n")
+
+
+def gen_main(f):
+    f.write("let main (series: []u8) (sliceLength: i32): [][]u8 =\n")
+    f.write("  slices series (i64.i32 sliceLength)\n")