I could not attempt 1 challenge out of 4 because i didnt get the question, and needed more information maybe another sample data? I was struggling for 30+ mins to understand the question but couldn't get any clues. I could not complete last challenge because of not understanding the question/pattern of question (maybe its my fault but a hint or 2 would have helped) rather than my coding ability. Maybe you can (as you work there) add 1 or 2 (optional) hints & make at least 2 samples of test data for tough questions. Anyways, it was a different and nice experience!