feat: add pop-count exercise (#3518)

* feat: add pop-count practice exercise

* config: del house, protein-trans from syllabus

As pop-count was added to the loop concept, house and protein translation were removed to keep the tree lean.

* Update config.json

On second (and third) thought, let's put pop-count first -- ahead of saddle points and OCR.  Feels like a better progression that way.

---------

Co-authored-by: BethanyG <BethanyG@users.noreply.github.com>

config.json

@@ -466,7 +466,7 @@
         "slug": "house",
         "name": "House",
         "uuid": "7c2e93ae-d265-4481-b583-a496608c6031",
-        "practices": ["loops"],
+        "practices": [],
         "prerequisites": [
           "basics",
           "lists",
@@ -680,7 +680,7 @@
         "slug": "protein-translation",
         "name": "Protein Translation",
         "uuid": "c89243f3-703e-4fe0-8e43-f200eedf2825",
-        "practices": ["loops"],
+        "practices": [],
         "prerequisites": [
           "basics",
           "conditionals",
@@ -968,6 +968,21 @@
         "prerequisites": ["basics", "bools", "numbers", "classes"],
         "difficulty": 2
       },
+      {
+        "slug": "pop-count",
+        "name": "Pop Count",
+        "uuid": "356e2d29-7efc-4fa3-bec7-8b61c3e967da",
+        "practices": ["loops"],
+        "prerequisites": [
+            "basics",
+            "lists",
+            "list-methods",
+            "loops",
+            "strings",
+            "string-methods"
+        ],
+        "difficulty": 3
+      },
       {
         "slug": "saddle-points",
         "name": "Saddle Points",

exercises/practice/pop-count/.docs/instructions.md

@@ -0,0 +1,8 @@
+# Instructions
+
+Your task is to count the number of 1 bits in the binary representation of a number.
+
+## Restrictions
+
+Keep your hands off that bit-count functionality provided by your standard library!
+Solve this one yourself using other basic tools instead.

exercises/practice/pop-count/.docs/introduction.md

@@ -0,0 +1,47 @@
+# Introduction
+
+Your friend Eliud inherited a farm from her grandma Tigist.
+Her granny was an inventor and had a tendency to build things in an overly complicated manner.
+The chicken coop has a digital display showing an encoded number representing the positions of all eggs that could be picked up.
+
+Eliud is asking you to write a program that shows the actual number of eggs in the coop.
+
+The position information encoding is calculated as follows:
+
+1. Scan the potential egg-laying spots and mark down a `1` for an existing egg or a `0` for an empty spot.
+2. Convert the number from binary to decimal.
+3. Show the result on the display.
+
+Example 1:
+
+```text
+Chicken Coop:
+ _ _ _ _ _ _ _
+|E| |E|E| | |E|
+
+Resulting Binary:
+ 1 0 1 1 0 0 1
+
+Decimal number on the display:
+89
+
+Actual eggs in the coop:
+4
+```
+
+Example 2:
+
+```text
+Chicken Coop:
+ _ _ _ _ _ _ _ _
+| | | |E| | | | |
+
+Resulting Binary:
+ 0 0 0 1 0 0 0 0
+
+Decimal number on the display:
+16
+
+Actual eggs in the coop:
+1
+```

exercises/practice/pop-count/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": ["vaeng"],
+  "files": {
+    "solution": [
+      "pop_count.py"
+    ],
+    "test": [
+      "pop_count_test.py"
+    ],
+    "example": [
+      ".meta/example.py"
+    ]
+  },
+  "blurb": "Count the 1 bits in a number",
+  "source": "Christian Willner, Eric Willigers",
+  "source_url": "https://forum.exercism.org/t/new-exercise-suggestion-pop-count/7632/5"
+}

exercises/practice/pop-count/.meta/example.py

@@ -0,0 +1,6 @@
+def egg_count(display_value):
+    eggs = 0
+    while display_value:
+        eggs += display_value % 2
+        display_value //= 2
+    return eggs

exercises/practice/pop-count/.meta/template.j2

@@ -0,0 +1,14 @@
+{%- import "generator_macros.j2" as macros with context -%}
+{{ macros.canonical_ref() }}
+
+{{ macros.header() }}
+
+class {{ exercise | camel_case }}Test(unittest.TestCase):
+    {% for case in cases -%}
+    def test_{{ case["description"] | to_snake }}(self):
+        expected = {{ case["expected"] }}
+        self.assertEqual(
+            {{ case["property"] | to_snake }}({{ case["input"]["number"] }}), expected
+        )
+
+    {% endfor %}

exercises/practice/pop-count/.meta/tests.toml

@@ -0,0 +1,22 @@
+# 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.
+
+[559e789d-07d1-4422-9004-3b699f83bca3]
+description = "0 eggs"
+
+[97223282-f71e-490c-92f0-b3ec9e275aba]
+description = "1 egg"
+
+[1f8fd18f-26e9-4144-9a0e-57cdfc4f4ff5]
+description = "4 eggs"
+
+[0c18be92-a498-4ef2-bcbb-28ac4b06cb81]
+description = "13 eggs"

exercises/practice/pop-count/pop_count.py

@@ -0,0 +1,2 @@
+def egg_count(display_value):
+    pass

exercises/practice/pop-count/pop_count_test.py

@@ -0,0 +1,27 @@
+# These tests are auto-generated with test data from:
+# https://github.com/exercism/problem-specifications/tree/main/exercises/pop-count/canonical-data.json
+# File last updated on 2023-10-18
+
+import unittest
+
+from pop_count import (
+    egg_count,
+)
+
+
+class PopCountTest(unittest.TestCase):
+    def test_0_eggs(self):
+        expected = 0
+        self.assertEqual(egg_count(0), expected)
+
+    def test_1_egg(self):
+        expected = 1
+        self.assertEqual(egg_count(16), expected)
+
+    def test_4_eggs(self):
+        expected = 4
+        self.assertEqual(egg_count(89), expected)
+
+    def test_13_eggs(self):
+        expected = 13
+        self.assertEqual(egg_count(2000000000), expected)