python: add problem 219 and unittest

Author: supercoderhawk

Python/sln_201_300/__init__.py

@@ -0,0 +1 @@
+# -*- coding: utf-8 -*-

Python/sln_201_300/solution_211_220.py

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+# -*- coding: utf-8 -*-
+from typing import List
+
+
+class Solution_211_220(object):
+    def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
+        """
+        219
+        :param nums:
+        :param k:
+        :return:
+        """
+        num2idx = {}
+        for idx, num in enumerate(nums):
+            if num in num2idx and idx - num2idx[num] <= k:
+                return True
+            num2idx[num] = idx
+
+        return False

Python/sln_201_300/test_solution_211_220.py

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+# -*- coding: utf-8 -*-
+from unittest import TestCase
+from sln_201_300.solution_211_220 import Solution_211_220
+
+
+class Test_Solution_211_220(TestCase):
+    def setUp(self) -> None:
+        self.sln = Solution_211_220()
+
+    def test_containsNearbyDuplicate(self):
+        nums = [1, 2, 3, 1]
+        self.assertEqual(self.sln.containsNearbyDuplicate(nums, 3), True)
+        self.assertEqual(self.sln.containsNearbyDuplicate([1, 0, 1, 1], 1), True)
+        self.assertEqual(self.sln.containsNearbyDuplicate([1, 2, 3, 1, 2, 3], 2), False)