The E problem is really well designed. Initially, my understanding of the scanline algorithm was focused on processing points within a two-dimensional range. Therefore, when analyzing the E problem, I enumerated all the values of $~a_i~$ and $~b_i~$ and treated them as prices, which we denote as val. At this point, the number of buyers among those who would not leave negative reviews is the count of $~a_i~$ that are greater than or equal to val. The number of buyers who would leave negative reviews is the count of $~b_i~$ that are greater than or equal to val, under the condition that $~a_i~$ for that $~b_i~$ is greater than val. Thus, I viewed this problem as counting points within a two-dimensional range, applying a scanline approach combined with offline processing using a Fenwick tree. However, the complexity of this approach prevented me from implementing it during the competition. After the contest, I was able to see a similar application of the scanline thinking, and the profound understanding of it truly opened my eyes. This also led me to reflect on the essence of the scanline preprocessing, which is to update all necessary states in a legal time complexity according to a certain order. It made me reconsider that in my code design, I should focus on specific implementation steps rather than just thinking about which algorithm to apply. This experience has been very educational and helpful for me! I really appreciate the design of the problems you created!
The E problem is really well designed. Initially, my understanding of the scanline algorithm was focused on processing points within a two-dimensional range. Therefore, when analyzing the E problem, I enumerated all the values of $~a_i~$ and $~b_i~$ and treated them as prices, which we denote as val. At this point, the number of buyers among those who would not leave negative reviews is the count of $~a_i~$ that are greater than or equal to val. The number of buyers who would leave negative reviews is the count of $~b_i~$ that are greater than or equal to val, under the condition that $~a_i~$ for that $~b_i~$ is greater than val. Thus, I viewed this problem as counting points within a two-dimensional range, applying a scanline approach combined with offline processing using a Fenwick tree. However, the complexity of this approach prevented me from implementing it during the competition. After the contest, I was able to see a similar application of the scanline thinking, and the profound understanding of it truly opened my eyes. This also led me to reflect on the essence of the scanline preprocessing, which is to update all necessary states in a legal time complexity according to a certain order. It made me reconsider that in my code design, I should focus on specific implementation steps rather than just thinking about which algorithm to apply. This experience has been very educational and helpful for me! I really appreciate the design of the problems you created!