The Warehouse Weight Pivot

In a logistics center, items are placed in a single row. Each item has a specific weight. Your task is to find the 'Weighted Pivot Index'. This is the 0-indexed position 'i' where the sum of weights of all items to the left of 'i' is exactly twice the sum of weights of all items to the right of 'i'. If multiple such indices exist, return the leftmost one. If no such index exists, return -1. Note: The sums do not include the weight of the item at index 'i' itself. The sum of zero elements is 0. Example: Input: 5 6 0 2 1 2 Output: 2 Explanation: Index 2 has value 2. Left sum (6+0) = 6. Right sum (1+2) = 3. Since 6 = 2 * 3, index 2 is the pivot.