While solving medium level questions on Leetcode, when I'm not able to solve a question in 15-20 minutes, I check its solutions from many resources, then write the algo in notes, and try to solve it without seeing the answer.

Many times, I've observed that when I encounter that question in an interview, I forget the algorithm. And sometimes, even if I remember the algorithm, I get stuck while coding especially in recursive solutions of Trees. I know that memorizing or cramming the solutions isn't the best way and I want to reach at a level where I can solve any Leetcode type question on my own in order to clear any interviews. So, can anyone here advice me on how do I improve myself in order to perform effectively during interviews?

Leetcode count: 235 (159 Easy, 75 Medium, 1 Hard).

P.S. Although I stuck in all kind of questions, but I am extremely weak at DP and Graphs.