"Sort Integers by The Number of 1 Bits" solution

src/sort_integers_by_the_number_of_1_bits.py

@@ -0,0 +1,7 @@
+def number_of_ones(num: int) -> int:
+    return bin(num)[2:].count("1")
+
+
+class Solution:
+    def sortByBits(self, arr: list[int]) -> list[int]:
+        return sorted(arr, key=lambda x: (number_of_ones(x), x))

tests/test_sort_integers_by_the_number_of_1_bits.py

@@ -0,0 +1,17 @@
+import pytest
+
+from src.sort_integers_by_the_number_of_1_bits import Solution
+
+
+@pytest.mark.parametrize(
+    "arr,expected",
+    (
+        ([0, 1, 2, 3, 4, 5, 6, 7, 8], [0, 1, 2, 4, 8, 3, 5, 6, 7]),
+        (
+            [1024, 512, 256, 128, 64, 32, 16, 8, 4, 2, 1],
+            [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024],
+        ),
+    ),
+)
+def test_solution(arr, expected):
+    assert Solution().sortByBits(arr) == expected