Earlier quoted context omitted.
Would you care to expand on how Anki helped you with Leetcode problems? Did you just think of a solution in your head and then compared it with the back of the card?
I put an href on the front side of the card to the problem, and most of the time actually clicked through and redid the problem from scratch (making sure to avert my eyes while I deleted LC's copy of my last attempt). If I felt particularly lazy or confident, I would just mentally sketch out the solution. Worth noting I also became much more adept at things like list comprehensions and using Counters and DefaultDicts…
I'm tempted to try it for my self. Did you only include problems that you solved previously?