The Bit-Flip Harvest

You are given an array of N integers. You can choose exactly one bit position B (0 to 30) and exactly one contiguous subarray [L, R]. For every element A[i] where L <= i <= R, you toggle bit B (if it was 0, it becomes 1; if it was 1, it becomes 0). Find the maximum possible sum of the array after this single operation. Input Format: An integer N, followed by N integers. Output Format: A single integer (the maximum sum). Example: Input: 4 1 2 4 8 Output: 18 (Explanation: Original sum is 15. Choose bit 0 and range [1, 3]. Elements 2, 4, 8 become 3, 5, 9. New sum: 1 + 3 + 5 + 9 = 18.)