These questions were asked in todays trilogy test. PLEASE DONT USE CHATGPT and PLEASE ANSWER wtih full explanation. Please explain the intution also in detail

You are given an array A of N integers. You will have to pick 3 subarrays from the array l1,l2 and l3. The subarray l1 must be a prefix and l3 must be a suffux. The minimum length of each of these subarrays must be 1 . An element of the array cannot be present in more than 1 of these subarrays. Find the maximum sum of all the elements in each of these three subarrays. Since the sum can be targe, return the positive remainder after dividing the sum with 109+7. Problem Constraints 3