You are given an integer array nums of length n.
Define the pulse value of an integer array arr as the alternating sum starting at index 0: pulse(arr) = arr[0] - arr[1] + arr[2] - arr[3] + ....
You may perform at most one operation on nums:
l and r such that 0 <= l < r < n.nums[l..r] by exactly one position. For example, [a, b, c, d] becomes [b, c, d, a].Return the maximum pulse value that can be obtained after performing at most one such operation.
Example 1:
Input: nums = [1,5,2]
Output: 6
Explanation:
1 - 5 + 2 = -2.nums[0..1] from [1, 5] to [5, 1].[5, 1, 2] and its pulse value is 5 - 1 + 2 = 6, which is the maximum possible.Example 2:
Input: nums = [6,4,3]
Output: 7
Explanation:
6 - 4 + 3 = 5.nums[1..2] from [4, 3] to [3, 4].[6, 3, 4] and its pulse value is 6 - 3 + 4 = 7, which is the maximum possible.Example 3:
Input: nums = [9,7]
Output: 2
Explanation:
The original pulse value is 9 - 7 = 2, which is already maximum. Thus, no rotation is required.
Constraints:
1 <= n == nums.length <= 105-109 <= nums[i] <= 109Loading editor...
[1,5,2]