The 3SUM problem represents a class of problems conjectured to require $Ω(n^2)$ time to solve, where $n$ is the size of the input. Given two polygons $P$ and $Q$ in the plane, we show that some variants of the decision problem, whether there exists a transformation of $P$ that makes it contained in $Q$, are 3SUM-Hard. In the first variant $P$ and $Q$ are any simple polygons and the allowed transformations are translations only; in the second and third variants both polygons are convex and we allow either rotations only or any rigid motion. We also show that finding the translation in the plane that minimizes the Hausdorff distance between two segment sets is 3SUM-Hard.
翻译:3SUM问题代表了一类被推测需要$Ω(n^2)$时间求解的问题,其中$n$为输入规模。给定平面上的两个多边形$P$和$Q$,我们证明了关于是否存在一种变换使$P$被$Q$包含的判定问题的若干变体是3SUM困难的。在第一个变体中,$P$和$Q$为任意简单多边形,且仅允许平移变换;在第二和第三个变体中,两个多边形均为凸多边形,我们分别仅允许旋转变换或允许任意刚体运动。我们还证明了在平面上寻找使两个线段集之间豪斯多夫距离最小的平移变换是3SUM困难的。