题解 | 两直线交点

point findMeetingPoint(line line_A,line line_B){
    point re(-1,-1);
    double a1,a2,b1,b2,c1,c2;
    a1=line_A.point_A.y-line_A.point_B.y;
    a2=line_B.point_A.y-line_B.point_B.y;
    b1=line_A.point_B.x-line_A.point_A.x;
    b2=line_B.point_B.x-line_B.point_A.x;
    if((a1*b2==a2*b1&&a1*a2*b1*b2!=0)||(a1==0&&a2==0)||(b1==0&&b2==0))
    return re;
    c1=line_A.point_A.x*line_A.point_B.y-line_A.point_B.x*line_A.point_A.y;
    c2=line_B.point_A.x*line_B.point_B.y-line_B.point_B.x*line_B.point_A.y;
    re.x=(b1*c2-b2*c1)/(b2*a1-b1*a2);
    re.y=(a1*c2-a2*c1)/(a2*b1-a1*b2);
    return re;
}