102025: [AtCoder]ABC202 F - Integer Convex Hull

Memory Limit:256 MB Time Limit:2 S
Judge Style:Text Compare Creator:
Submit:0 Solved:0

Description

Score : $600$ points

Problem Statement

We have $N$ points $P_1, P_2, \dots, P_N$ on a plane. The coordinates of $P_i$ is $(X_i, Y_i)$. We know that no three points lie on the same line.

For a subset $S$ of $\{ P_1, P_2, \dots, P_N \}$ with at least three elements, let us define the convex hull of $S$ as follows:

  • The convex hull is the convex polygon with the minimum area such that every point of $S$ is within or on the circumference of that polygon.

Find the number, modulo $(10^9 + 7)$, of subsets $S$ such that the area of the convex hull is an integer.

Constraints

  • $3 \leq N \leq 80$
  • $0 \leq |X_i|, |Y_i| \leq 10^4$
  • No three points lie on the same line.
  • All values in input are integers.

Input

Input is given from Standard Input in the following format:

$N$
$X_1$ $Y_1$
$X_2$ $Y_2$
$\vdots$
$X_N$ $Y_N$

Output

Print the answer. Note that you are asked to find the count modulo $(10^9 + 7)$.


Sample Input 1

4
0 0
1 2
0 1
1 0

Sample Output 1

2

$ \{ P_1, P_2, P_4 \}$ and $\{ P_2, P_3, P_4 \}$ satisfy the condition.


Sample Input 2

23
-5255 7890
5823 7526
5485 -113
7302 5708
9149 2722
4904 -3918
8566 -3267
-3759 2474
-7286 -1043
-1230 1780
3377 -7044
-2596 -6003
5813 -9452
-9889 -7423
2377 1811
5351 4551
-1354 -9611
4244 1958
8864 -9889
507 -8923
6948 -5016
-6139 2769
4103 9241

Sample Output 2

4060436

Input

题意翻译

hhoppitree 给了你平面直角坐标系中的 $n$ 个点,**保证无三点共线**,现在他想要从中选出**至少三个**点,使得这个点集所构成的凸包的面积为整数,求有多少种方案。

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