Merge pull request #3 from maxicot/heapsort

Implement heapsort

Author: maxicot

.github/workflows/python.yml

@@ -14,6 +14,7 @@ jobs:
           python -m pip install --upgrade pip
           pip install ruff
           pip install pytest
+          pip install -r requirements.txt
       # Update output format to enable automatic inline annotations.
       - name: Run Ruff
         run: ruff check --output-format=github .

heapsort/__init__.py

@@ -0,0 +1,41 @@
+from collections.abc import Callable
+from typing import TypeVar
+
+T = TypeVar("T")
+
+
+# Recursive heapsort implementation.
+# The default behavior of `cmp` is to check
+# whether the first argument is smaller than the second.
+# A custom `cmp` is mandatory in case `T` doesn't support comparisons
+def heapsort(array: list, cmp: Callable[[T, T], bool] = lambda x, y: x < y) -> list:
+    n = len(array)
+
+    if n < 2:
+        return array
+
+    def heapify(array: list, n: int, i: int) -> list:
+        left = 2 * i + 1
+        right = left + 1
+        largest = i
+
+        if left < n and cmp(array[largest], array[left]):
+            largest = left
+
+        if right < n and cmp(array[largest], array[right]):
+            largest = right
+
+        if largest != i:
+            (array[i], array[largest]) = (array[largest], array[i])
+            return heapify(array, n, largest)
+
+        return array
+
+    for i in range(n // 2, -1, -1):
+        array = heapify(array, n, i)
+
+    for i in range(n - 1, 0, -1):
+        (array[i], array[0]) = (array[0], array[i])
+        array = heapify(array, i, 0)
+
+    return array

heapsort/src/lib.py

@@ -0,0 +1,37 @@
+from hypothesis import given
+from hypothesis import strategies as st
+
+from ..src.lib import heapsort
+
+
+def test_general():
+    assert heapsort([0, 8, 3, -1, 5]) == [-1, 0, 3, 5, 8]
+    assert heapsort([0, 8, 3, -1, 5], cmp=lambda x, y: x > y) == [8, 5, 3, 0, -1]
+
+
+def test_special():
+    assert heapsort([]) == []
+    assert heapsort([1]) == [1]
+
+
+@given(st.lists(st.integers(), max_size=100))
+def test_property(arr):
+    assert heapsort(arr) == sorted(arr)
+
+
+class Custom:
+    def __init__(self, n: int):
+        self.inner = n
+
+    def __eq__(self, rhs) -> bool:
+        return self.inner == rhs.inner
+
+    def into(self) -> int:
+        return self.inner
+
+
+def test_custom():
+    assert heapsort([Custom(2), Custom(1)], cmp=lambda x, y: x.inner < y.inner) == [
+        Custom(1),
+        Custom(2),
+    ]

heapsort/tests/__init__.py

@@ -13,3 +13,7 @@
       "RET",      # Хорошие практики возврата
       "SIM",      # Общие правила упрощения
   ]
+
+[tool.pytest.ini_options]
+  python_files = "*.py"
+  testpaths = ["./*/tests"]

heapsort/tests/test.py

@@ -0,0 +1 @@
+hypothesis