Solution to Codility Max Double Slice Sum problem.

We can use Kadane’s algorithm from two directions. First, we can safely ignore `A[0]`

and `A[N-1]`

since by definition they can’t be a part of any double-slice sum.

Now, define `K1[i]`

as the maximum sum contiguous subsequence ending at index \(i\), and similarly, define `K2[i]`

as the maximum sum contiguous subsequence starting with index \(i\).

Then, iterate over \(i\), and find the maximum sum of `K1[i-1]+K2[i+1]`

. This is the max double slice sum.

The 100/100 Java code: