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.

中文翻译：

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将不相交的线段链接成一个简单的多边形很困难

确定平面中不相交的线段族是否可以通过在端点之间添加线段来链接成一个简单的多边形（或一个简单的多边形链）是 NP 难的。