I discovered this amazing YouTube channel recently that I wish I had access to back in college. It explains some very difficult math concepts in a very simple and easy to understand way: https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw
It's amazing how seeing something visually or having someone else solve something can aid in your understanding of a topic. I remember having the most difficult time understanding mergesort from my book's pseudocode and my professor's lecture. But seeing mergesort in action on youtube revealed what it truly was and made what seemed impossibly complex, so simple and elegant.