Find Missing Integer

Problem Overview

• Core task: find the kth smallest positive integer missing from the array.
• Inputs: int arr[n] (dataset) and long k; Output: long for the kth missing positive.
• Constraints: 0 ≤ i < n; positive integers start at 1; array may have duplicates.
• Domain: data analysis and machine learning context; a common coding interview problem and interview question.