Create 1191-k-concatenation-maximum-sum.js

Author: everthis

1191-k-concatenation-maximum-sum.js

@@ -0,0 +1,26 @@
+/**
+ * @param {number[]} arr
+ * @param {number} k
+ * @return {number}
+ */
+const kConcatenationMaxSum = function(arr, k) {
+  const MOD = 1e9 + 7,
+    INF = 1e4 + 1;
+  const kadane = (A, sum = 0, ans = -INF) => {
+    for (let x of A) {
+      sum = Math.max(0, sum + x);
+      ans = Math.max(ans, sum);
+    }
+    return [sum, ans];
+  };
+  const [sum1, ans1] = kadane(arr);
+  const [sum2, ans2] = kadane(arr, sum1);
+  const [sum3, ans3] = kadane(arr, sum2);
+  const delta1 = ans2 - ans1,
+    delta2 = ans3 - ans2;
+  return k == 1 || delta1 == 0
+    ? ans1
+    : delta2 == 0
+    ? ans2
+    : ans1 + ((delta1 * (k - 1)) % MOD);
+};