I have been trying to cover inteeview questions for some times now. But I still struggle if I see a new question in interview. TBH I am unable to solve any of the questions on my own as well. I try to struggle to 20-30 mins and then try to look for explainations. And then its give a sense of understanding and in a way I try to memorize the logic or the solution.

1. I feel like this way of approaching problem wont be helping me.How do you guys practice? How long should I try to solve any question before looking for answer?
2. How to not forget already solved problems in a month? Do you guys revise the problem or the concepts?
3. I want to restart my learning process again (if that's possible), how much time should I give myself to acheive a decent confidence level.

Anything would be a help. :) Thanks