I actually used Anki cards to study LeetCode problems when preparing for interviews and it seemed to help. After doing a problem and solving it I created the card as such:

- Front of card is the entire LC problem statement

- Back is a bulleted list of the steps or key points (ie. first I notice this list is unsorted, so I would sort first, next I would do blah blah..)

- Back also contains the code solution that I might just glance through or look at a particular part of it.