Given an array of distinct integers arr sorted in ascending order, return the smallest index i such that arr[i] == i. If no such index exists, return $-1$.

Constraints:

• $1 \leq$ arr.length $< 10^4$

• $-10^9 \leq$ arr[i] $\leq 10^9$

Now, let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.