Deciding whether a family of disjoint line segments in the plane can be linked into a simple polygon (or a simple polygonal chain) by adding segments between their endpoints is NP-hard.

翻译：决定平面上一条互不连接的线段是否可以通过在端点之间添加端点为 NP-hard 的区段而连接成一个简单的多边形(或一个简单的多边形链条) 。