3427. Sum of Variable Length Subarrays

You are given an integer array nums of size n. For each index i where 0 <= i < n, define a subarray nums[start ... i] where start = max(0, i - nums[i]). Return the total sum of all elements from the subarray defined for each index in the array. Example 1: Input: nums = [2,3,1] Output: 11 Explanation: i Subarray Sum 0 nums[0] = [2] 2 1 nums[0 ... 1] = [2, 3] 5 2 nums[1 ... 2] = [