Implement a Given Array Algorithm (Iterative Reduction by First Non-zero)

Given a non-negative integer array nums, run the following procedure and return the final value res: Initialize res = 0. Repeat until there is no positive number left: Scan from left to right to find the first positive element; let its value be x. If none exists, stop. Starting from that index, scan rightward: If nums[j] < x, stop this scan (go to step 3). Otherwise set nums[j] -= x and continue. Add x to res and go back to step 1. Output res. Input Line 1: integer n Line 2: n non-negative integers nums Output Integer res. (Constraints depend on the OA; assume up to 2e5 elements.) Example Input 5 0 3 3 1 5 Output 4