Elf on the Shelf

After helping Santa [get some exercise](https://www.facebook.com/codingcompetitions/hacker-cup/2023/round-1/problems/A), you (Santa's little helper) think it's time the elves get around to actually working on toys. Santa Claus Lane is home to $N$ elves, the $i$-th of whom lives $X_i$ meters from the start of the lane. You are, once again, tasked to assign elves to work on toys for good little g