title: How to check whether 2 lines segments intersect?
body: <p>How do I check whether 2 line segments,  L1(p1,p2) and L2(p3,p4), intersect with each other? I do not need the intersection point, I just need to know whether they intersect or not. Since my application calculating this a lot, I need to find a fast solution.</p>
  
  <p>Thanks </p>