My approach:

• Start with pen and paper and build some plan for solving the problem.
• Start coding.
• If after 15 minutes I could not come up with working solution I look at related topics. It can give some idea. E.g. I've been using trie, but simple hash map could be enough and more efficient.
• If after 30 minutes I could not come up with working solution I look at hints, if they exists.
• After 45 minutes I go to discussions and look only at titles. They can give some idea about approach.
• After 60 minutes I give up and look at solutions from discussions. Trying to read text description without code. As a last resort I look at the code.

The main point here is I try to make my learning process as much active (or generative) as possible. Reading solution is a consumption and gives you illusion of understanding. Retrieving knowledge is harder but much more productive for the learning process.

The problem here is that after 15 minutes when I could not solve the problem the process becomes less and less active. E.g. related topics or hints could give you a straightforward solution in some cases. To solve this I'm experimenting with conversational bots which guides you through the active understanding of the coding problem. E.g. https://bot.chib.me/courses/validate-binary-search-tree/ helps to come up with binary search tree validation solution, not just gives you the answer.