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

Author: kamyu104

C++/maximum-subarray-sum-with-length-divisible-by-k.cpp

@@ -0,0 +1,21 @@
+// Time:  O(n)
+// Space: O(k)
+
+// prefix sum, dp
+class Solution {
+public:
+    long long maxSubarraySum(vector<int>& nums, int k) {
+        static const int64_t INF = numeric_limits<int64_t>::max();
+        vector<int64_t> dp(k, INF);
+        dp.back() = 0;
+        int64_t result = numeric_limits<int64_t>::min();
+        for (int64_t i = 0, curr = 0; i < size(nums); ++i) {
+            curr += nums[i];
+            if (dp[i % k] != INF) {
+                result = max(result, curr - dp[i % k]);
+            }
+            dp[i % k] = min(dp[i % k] , curr);
+        }
+        return result;
+    }
+};