- Time limit: 1.00 s
- Memory limit: 512 MB
You may assume that no parallel line segments overlap, and no two line segments have a common endpoint.
The first input line has an integer $n$: the number of line segments.
Then there are $n$ lines describing the line segments. Each line has four integers: $x_1$, $y_1$, $x_2$ and $y_2$: a line segment begins at point $(x_1,y_1)$ and ends at point $(x_2,y_2)$.
Print the number of intersection points.
- $1 \le n \le 10^5$
- $-10^6 \le x_1 \le x_2 \le 10^6$
- $-10^6 \le y_1 \le y_2 \le 10^6$
2 3 7 3
3 1 3 5
6 2 6 6