Solve "Sort Characters By Frequency"

Author: lancelote

src/sort_characters_by_frequency.py

@@ -0,0 +1,12 @@
+from collections import Counter
+
+
+class Solution:
+    def frequencySort(self, s: str) -> str:
+        result: list[str] = []
+        counter = Counter(s)
+
+        for char, count in counter.most_common():
+            result.append(char * count)
+
+        return "".join(result)

tests/test_sort_characters_by_frequency.py

@@ -0,0 +1,15 @@
+import pytest
+
+from src.sort_characters_by_frequency import Solution
+
+
+@pytest.mark.parametrize(
+    "s,expected",
+    (
+        ("tree", "eetr"),
+        ("cccaaa", "cccaaa"),
+        ("Aabb", "bbAa"),
+    ),
+)
+def test_solution(s, expected):
+    assert Solution().frequencySort(s) == expected