Array Reduction 1

Problem Overview

• Task: Given an array num[], repeatedly pick two different elements, remove them, append their sum, and pay a cost equal to that sum; compute the minimum total cost to end with one element.
• Input/Output: int num[n] → returns an int (minimum total cost).
• Constraints: 2 ≤ n ≤ 10^4, 0 ≤ num[i] ≤ 10^5.
• Context: Cost-optimization array aggregation problem common in coding interview settings.
• Source: Oracle interviews; classic interview question.