- Time limit: 1.00 s
- Memory limit: 512 MB
Given n horizontal and vertical line segments, your task is to calculate the number of their intersection points.
You can assume that no parallel line segments intersect, and no endpoint of a line segment is an intersection point.
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
- (x_1,y_1) \neq (x_2,y_2)
3 2 3 7 3 3 1 3 5 6 2 6 6