Add problem 209 - Minimum Size Subarray Sum

Author: anirudhology

problems/sliding_window/minimum_size_subarray_sum.py

@@ -0,0 +1,27 @@
+from typing import List
+
+
+class MinimumSizeSubarraySum:
+    @staticmethod
+    def minSubArrayLen(target: int, nums: List[int]) -> int:
+        # Special case
+        if not nums:
+            return 0
+        # Length of list
+        n = len(nums)
+        # Left and right pointers of the window
+        left, right = 0, 0
+        # Minimum length
+        min_length = 1 << 31 - 1
+        # Sum of the window
+        window_sum = 0
+        # Process the list
+        while right < n:
+            window_sum += nums[right]
+            right += 1
+            # Squeeze the window, if possible
+            while window_sum >= target:
+                min_length = min(min_length, right - left)
+                window_sum -= nums[left]
+                left += 1
+        return 0 if min_length == 1 << 31 - 1 else min_length

tests/sliding_window/minimum_size_subarray_sum_test.py

@@ -0,0 +1,31 @@
+import unittest
+
+from problems.sliding_window.minimum_size_subarray_sum import MinimumSizeSubarraySum
+
+
+class TestMinimumSizeSubarraySum(unittest.TestCase):
+
+    def setUp(self):
+        self.minimum_size_subarray_sum = MinimumSizeSubarraySum()
+
+    def test_min_sub_array_len_empty_array(self):
+        self.assertEqual(self.minimum_size_subarray_sum.minSubArrayLen(7, []), 0)
+
+    def test_min_sub_array_len_null_array(self):
+        self.assertEqual(self.minimum_size_subarray_sum.minSubArrayLen(7, None), 0)
+
+    def test_min_sub_array_len_no_subarray_exists(self):
+        self.assertEqual(self.minimum_size_subarray_sum.minSubArrayLen(15, [1, 2, 3, 4, 5]), 5)
+
+    def test_min_sub_array_len_exact_match(self):
+        self.assertEqual(self.minimum_size_subarray_sum.minSubArrayLen(7, [2, 3, 1, 2, 4, 3]), 2)
+
+    def test_min_sub_array_len_multiple_matches(self):
+        self.assertEqual(self.minimum_size_subarray_sum.minSubArrayLen(4, [1, 4, 4]), 1)
+
+    def test_min_sub_array_len_single_element(self):
+        self.assertEqual(self.minimum_size_subarray_sum.minSubArrayLen(3, [3]), 1)
+
+
+if __name__ == '__main__':
+    unittest.main()