Given an integer array nums, a subsequence is defined as a good subsequence if the absolute difference between every pair of consecutive elements in the subsequence is exactly $1$.

Return the total sum of all elements across all possible good subsequences of nums. Since the answer may be very large, return it modulo $10^9 + 7$.

Constraints:

• $1 \leq$ nums.length $\leq 10^5$

• $0 \leq$ nums[i] $\leq 10^5$

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.