Create maximum-subarray-sum-with-length-divisible-by-k.py

Author: kamyu104

Python/maximum-subarray-sum-with-length-divisible-by-k.py

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+# Time:  O(n)
+# Space: O(k)
+
+# prefix sum, dp
+class Solution(object):
+    def maxSubarraySum(self, nums, k):
+        """
+        :type nums: List[int]
+        :type k: int
+        :rtype: int
+        """
+        dp = [float("inf")]*k
+        dp[-1] = 0
+        curr = 0
+        result = float("-inf")
+        for i, x in enumerate(nums):
+            curr += x
+            result = max(result, curr-dp[i%k])
+            dp[i%k] = min(dp[i%k], curr)
+        return result