I have been doing continious preactising on leetcode for more than a month now. At this point I am able to solve most of the medium level problems without much of a struggle. But when it comes to the hard problems, espacially from the recent competitions, I really do struggle to solve them. To be more specific I will link some of the problems below.\nhttps://leetcode.com/problems/allocate-mailboxes/\nhttps://leetcode.com/problems/parallel-courses-ii/\nhttps://leetcode.com/problems/max-value-of-equation/\nhttps://leetcode.com/problems/minimum-possible-integer-after-at-most-k-adjacent-swaps-on-digits/\nNot matter how hard I try to come to the solution, I still am not able to solve it.  It is clear to me that I need to practise more, but can someone suggest how to train on leetcode so that solutions to these type of problems comes naturally. It would really appreciate if you could share how you become comfortable with these type of problems.\nThanks in Advance

I have been doing continious preactising on leetcode for more than a month now. At this point I am able to solve most of the medium level problems without much 