Given an integer array nums, choose indices i and j such that i < j and nums[i] < nums[j]. Define the value of this pair as nums[j] - nums[i].

Return the maximum possible value over all valid pairs. If no valid pair exists, return $-1$.

Constraints:

• n == nums.length

• $2 \leq$ n $\leq 1000$

• $1 \leq$ nums[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.