How to think about the following problem

Revision en1, by X-O__O-X, 2020-10-01 06:23:41

This problem is the type of problem where I know everything needed but I still can't solve it. I always learn a lot from such problems

I am not interested in a solution, I know it, but how to approach the problem and reach a solution. How to think about it? What should have hinted me to consider using what was needed to solve it ?


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en1 English X-O__O-X 2020-10-01 06:23:41 427 Initial revision (published)