This wave seems to be difficult. . . .
Let's read a wave of questions first, and found that question b ([CF838-B] Diverging Directions) seems to be very watery. . . dfs sequence + line segment tree messing can come out. . Then I code for 1.5 hours and pass the sample. I feel that the sample is not very watery, so I don't care. (flag1)
Then just after C (Hnoi2018 game) is not very good, I wrote an O(n^2) and got rough
A has no idea a... (Hnoi2018 Road) I feel that the depth is less than 40. I wrote a memory search, and this space feels a little empty. I think it's better to change it to a smaller size. Anyway, it's A no (flag2)
D (Hnoi2013 slicing cakes) The meaning of the question is so difficult to understand, just ignore the violence
Expecting 30+100+20+10=160 seems to be OK?
Actual 60+0+20+0=80
Dish. . When the t1 array is opened, it becomes AC. .
B didn't take a picture and then hung up the situation, the retribution of the lazy
Grandpa Karma actually messed around with random numbers and turned O(n^2 ) into O(nlogn )
D can actually do it. . min cut
Remember to write and take pictures in the future, and have patience to read the questions. Thank you. . .