Hello Codeforces community ! Recently I found out that I am very weak at problems that require quick and precise observation, like 1330D, like I always solve these kinds of problem way to slow or unable to solve them at all. Can you please suggest problems like that ? I know there is tags in problemset, but I believe good problems recommended by people who solved them will be more beneficial for me and other people aswell. Thanks in advance.

Problem statement

I can see that processing the segments from high to low and using segment tree to update the segment currently covering an interval l, r is necessary to solve this problem. However, i couldn't think of a way to update the segment currently covering l, r as there can be multiple segments that were covering it. Can someone please help ?