general swe
题目如下
A valid tail-sequence of an array meets the following criteria:
Contains multiple consecutive elements of the array
Contains the first OR last element of the array
Does not contain the first AND last element of the array
As an example, for array, [1, 2, 3, 4], the valid tail-sequences are:
[1, 2], [1, 2, 3], [2, 3, 4], [3, 4]
Implement a function, aggregateMaxTailSequenceSums(), which:
Accepts argument:
An array of integers
Outputs:
An integer which is the maximum possible sum of all elements using one or more tail-sequences found in the array
If no tail-sequence exists in the array, the function should return null
Example 1:
Input: [-2, 3, -1, 2, 0]
Output: 10
Explanation: using tail-sequences [-2, 3] => 1, [-2, 3, -1, 2] => 2, [3, -1, 2, 0] => 4, [-1, 2, 0] => 1, [2, 0] => 2
1 + 2 + 4 + 1 + 2 = 10
Example 2:
Input: [1, -6, 2, -7, 4, -4]
Output: 0
Explanation: using tail-sequence [4, -4]
Example 3:
Input: [-1, -2, -4, 1]
Output: -3
Explanation: using either tail-sequence [-1, -2] or [-4, 1]