CountDistinctArrangements is the speedy and correct implementation Adapters can only connect to a source 1-3 jolts lower than its rating The charging outlet has an effective rating of 0 jolts, so the only adapters that could connect to it directly would need to have a joltage rating of 1, 2, or 3 jolts.

Below here is a tree implementation Building the tree will correctly count the number of paths, however, it is extremely slow on datasets much larger than 50 numbers Was an interesting study in creation and runtime issues.