Given two sets $\mathit{R}$ and $\mathit{B}$ of at most $\mathit{n}$ points in the plane, we present efficient algorithms to find a two-line linear classifier that best separates the ``red'' points in $\mathit{R}$ from the ``blue'' points in $B$ and is robust to outliers. More precisely, we find a region $\mathit{W}_\mathit{B}$ bounded by two lines, so either a halfplane, strip, wedge, or double wedge, containing (most of) the blue points $\mathit{B}$, and few red points. Our running times vary between optimal $O(n\log n)$ and $O(n^4)$, depending on the type of region $\mathit{W}_\mathit{B}$ and whether we wish to minimize only red outliers, only blue outliers, or both.
翻译:给定平面内最多 $\mathit{n}$ 个点构成的两个集合 $\mathit{R}$ 和 $\mathit{B}$,我们提出高效算法以寻找能够最佳分离 $\mathit{R}$ 中的“红色”点与 $\mathit{B}$ 中的“蓝色”点,且对离群点具有鲁棒性的双线线性分类器。更精确地说,我们寻找一个由两条线围成的区域 $\mathit{W}_\mathit{B}$(可以是半平面、条带、楔形或双楔形),使其包含(大部分)蓝色点 $\mathit{B}$,而仅包含少量红色点。根据区域 $\mathit{W}_\mathit{B}$ 的类型以及我们是希望仅最小化红色离群点、仅最小化蓝色离群点,还是同时最小化两者,我们的运行时间介于最优的 $O(n\log n)$ 与 $O(n^4)$ 之间。