#AT2162. F - One Fourth
F - One Fourth
F - One Fourth
Score : $500$ points
Problem Statement
ABC 250 is a commemorable quarter milestone for Takahashi, who aims to hold ABC 1000, so he is going to celebrate this contest by eating as close to $1/4$ of a pizza he bought as possible.
The pizza that Takahashi bought has a planar shape of convex $N$-gon. When the pizza is placed on an $xy$-plane, the $i$-th vertex has coordinates $(X_i, Y_i)$.
Takahashi has decided to cut and eat the pizza as follows.
- First, Takahashi chooses two non-adjacent vertices from the vertices of the pizza and makes a cut with a knife along the line passing through those two points, dividing the pizza into two pieces.
- Then, he chooses one of the pieces at his choice and eats it.
Let $a$ be the quarter ($=1/4$) of the area of the pizza that Takahashi bought, and $b$ be the area of the piece of pizza that Takahashi eats. Find the minimum possible value of $8 \times |a-b|$. We can prove that this value is always an integer.
Constraints
- All values in input are integers.
- $4 \le N \le 10^5$
- $|X_i|, |Y_i| \le 4 \times 10^8$
- The given points are the vertices of a convex $N$-gon in the counterclockwise order.
Input
Input is given from Standard Input in the following format:
Output
Print the answer as an integer.
5
3 0
2 3
-1 3
-3 1
-1 -1
1
Suppose that he makes a cut along the line passing through the $3$-rd and the $5$-th vertex and eats the piece containing the $4$-th vertex.
Then, $a=\frac{33}{2} \times \frac{1}{4} = \frac{33}{8}$, $b=4$, and $8 \times |a-b|=1$, which is minimum possible.
4
400000000 400000000
-400000000 400000000
-400000000 -400000000
400000000 -400000000
1280000000000000000
6
-816 222
-801 -757
-165 -411
733 131
835 711
-374 979
157889