Merge pull request #1 from 2400031598/2400031598-patch-1

Create maxAlternatingSum.java

Author: 2400031598

maxAlternatingSum.java

@@ -0,0 +1,18 @@
+import java.util.*;
+
+class Solution {
+    public long maxAlternatingSum(int[] nums) {
+        int n = nums.length;
+        int posCounts = (n + 1) / 2;
+        Integer[] absVals = Arrays.stream(nums).map(Math::abs).boxed().toArray(Integer[]::new);
+  Arrays.sort(absVals, (a, b) -> Integer.compare(b, a));
+
+        long sumPos = 0, sumNeg = 0;
+        for (int i = 0; i < n; i++) {
+            long sq = 1L * absVals[i] * absVals[i];
+            if (i < posCounts) sumPos += sq;
+            else sumNeg += sq;
+        }
+        return sumPos - sumNeg;
+    }
+}