Mex Path

You're given an array $A$ of size $N$. There is a [complete](https://en.wikipedia.org/wiki/Complete_graph) [weighted](https://en.wiktionary.org/wiki/weighted_graph) graph with $N$ nodes and $\frac{N \cdot (N-1)}{2}$ undirected weighted edges. The weight of edge between node $i$ and node $j$ is determined as $\text{MEX}(A_i, A_{i+1}, \ldots, A_j)$. Your task is to find the [shortest path](http