Given an integer array arr, count the total number of elements x such that x + 1 is also present in arr.

If there are duplicate values in arr, each occurrence of x should be counted separately as long as x + 1 exists in arr.

Constraints:

• $1 \leq$ arr.length $\leq 1000$

• $0 \leq$ arr[i] $\leq 1000$

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.