Modify Array

Problem Overview

• Determine the minimum total cost to modify elements so the array becomes non-decreasing (ascending) or non-increasing (descending).
• Input: int arr[n]; Output: an integer minimal cost; Constraints: 1 ≤ n ≤ 10^3, 1 ≤ arr[i] ≤ 10^9.
• Cost of changing an element equals the absolute difference between its original and new value.
• Applicable to data normalization and sequence adjustment scenarios requiring ordered outcomes.
• Asked in Paypal interviews; a coding interview problem and common interview question.