I've following problem statement at hand, I came across an interesting 2 liner, C solution for it under leedcode discussion section. I tried to decompose it to understand what it means, and except one small line, I understood the rest. My question is at the end.
Leetcode Problem Statement:
Given an array arr of positive integers sorted in a strictly increasing order, and an integer k. Find the kth positive integer that is missing from this array.