I found the recursive and savings problems relatively straightforward. However, as I haven't had much practice with hashmaps before, I had to do a lot of trial and error and the instructions for the second lowest problem were a little confusing as the example output didn't match up. Should secondLowest( [4, 3, 1, 1, 2] ) === 1 be === 2 instead?
In the time I had, I did my best to follow the instructions and come up with a workable solution. If I had more time, I would give the longest sequence problem another try because I know I'm really close!