You are given two gene strings startGene and endGene, along with a list bank of valid gene strings. A single mutation changes exactly one character in the current gene to a different character.

Return the minimum number of mutations needed to transform startGene into endGene, where every intermediate gene string produced during the process must appear in bank. If it is impossible to reach endGene under these rules, return $-1$.

Implement int minMutation(str startGene, str endGene, List[str] bank).

Note: Each mutation must change exactly one position, and every intermediate gene must be contained in bank.

Constraints:

• $0 \leq$ bank.length $\leq 10$

• startGene.length $==$ endGene.length $==$ bank[i].length $== 8$

• startGene, endGene, and bank[i] consist only of the characters ['A', 'C', 'G', 'T']

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.