2019 杭电多校训练第 9 场

rank	solved	A	B	C	D	E	F	G	H	I	J	K
267	4	Ø	O	.	.	O	!	Ø	.	.	.	.

A

UpSolved by Forsaken.

可以推出一个和调和级数前缀和有关的式子，分段打表即可。

B

Solved by XLor.

答案个数等于交点数加一，扫描线即可。

E

Solved by XLor.

G

UpSolved by XLor.

按直径剖分，讨论两种情况，打标记。