Neighborhood Problem

Given a list of houses and roads connecting them, write a function to find all of the houses accessable by road from any arbitrary house.

For example, given the following neighborhood:

We can represent the roads in this neighborhood with the following array of arrays:

And we expect that for the input "A", our function will return ["B", "C", "E", "F"] in some order. For input "D" our function will return ["G", "H"] in some order.

Here is a more complicated neighborhood to test your processing on:

Which is described by

Specifically, make sure: