diff --git a/medium/sort_colors.py b/medium/sort_colors.py
new file mode 100644
index 0000000..9161116
--- /dev/null
+++ b/medium/sort_colors.py
@@ -0,0 +1,22 @@
+# https://leetcode.com/problems/sort-colors
+
+from typing import List
+
+class Solution:
+    def sortColors(self, nums: List[int]) -> None:
+        def swap(i: int, j: int):
+            nums[i], nums[j] = nums[j], nums[i]
+        i = 0
+        j = 0
+        k = len(nums) - 1
+        while j <= k:
+            if nums[j] < 1:
+                swap(i, j)
+                i += 1
+                j += 1
+            elif nums[j] > 1:
+                swap(j, k)
+                k -= 1
+            else:
+                j += 1
+