Given two strings source and target, return the minimum number of subsequences of source that can be concatenated to form target. If it is impossible to construct target in this manner, return $-1$.

A subsequence of a string is a new string generated from the original string by deleting some or none of the characters without changing the relative order of the remaining characters.

Constraints:

• $1 \leq$ source.length, target.length $\leq 1000$

• source and target consist of lowercase English letters.

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.