{"title":"关于简单多边形的平面快速三角剖分","authors":"Stefan Hertel, Kurt Mehlhorn","doi":"10.1016/S0019-9958(85)80044-9","DOIUrl":null,"url":null,"abstract":"<div><p>Let <em>P</em><sub>1</sub>,…, <em>P<sub>k</sub></em> be pairwise non-intersecting simple polygons with a total of <em>n</em> vertices and <em>s</em> start vertices. A start vertex, in general, is a vertex both of which neighbors have larger <em>x</em> coordinate. We present an algorithm for triangulating <em>P</em><sub>1</sub>,…, <em>P<sub>k</sub></em> in time <em>O</em>(<em>n</em> + <em>s</em> log <em>s</em>). <em>s</em> may be viewed as a measure of non-convexity. In particular, <em>s</em> is always bounded by the number of concave angles + 1, and is usually much smaller. We also describe two new applications of triangulation. Given a triangulation of the plane with respect to a set of <em>k</em> pairwise non-intersecting simple polygons, then the intersection of this set with a convex polygon <em>Q</em> can be computed in time linear with respect to the combined number of vertices of the <em>k</em> + 1 polygons. Such a result had only be known for two <em>convex polygons</em>. The other application improves the bound on the number of convex parts into which a polygon can be decomposed.</p></div>","PeriodicalId":38164,"journal":{"name":"信息与控制","volume":"64 1","pages":"Pages 52-76"},"PeriodicalIF":0.0000,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0019-9958(85)80044-9","citationCount":"16","resultStr":"{\"title\":\"Fast triangulation of the plane with respect to simple polygons\",\"authors\":\"Stefan Hertel, Kurt Mehlhorn\",\"doi\":\"10.1016/S0019-9958(85)80044-9\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Let <em>P</em><sub>1</sub>,…, <em>P<sub>k</sub></em> be pairwise non-intersecting simple polygons with a total of <em>n</em> vertices and <em>s</em> start vertices. A start vertex, in general, is a vertex both of which neighbors have larger <em>x</em> coordinate. We present an algorithm for triangulating <em>P</em><sub>1</sub>,…, <em>P<sub>k</sub></em> in time <em>O</em>(<em>n</em> + <em>s</em> log <em>s</em>). <em>s</em> may be viewed as a measure of non-convexity. In particular, <em>s</em> is always bounded by the number of concave angles + 1, and is usually much smaller. We also describe two new applications of triangulation. Given a triangulation of the plane with respect to a set of <em>k</em> pairwise non-intersecting simple polygons, then the intersection of this set with a convex polygon <em>Q</em> can be computed in time linear with respect to the combined number of vertices of the <em>k</em> + 1 polygons. Such a result had only be known for two <em>convex polygons</em>. The other application improves the bound on the number of convex parts into which a polygon can be decomposed.</p></div>\",\"PeriodicalId\":38164,\"journal\":{\"name\":\"信息与控制\",\"volume\":\"64 1\",\"pages\":\"Pages 52-76\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1985-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/S0019-9958(85)80044-9\",\"citationCount\":\"16\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"信息与控制\",\"FirstCategoryId\":\"1093\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0019995885800449\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"Mathematics\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"信息与控制","FirstCategoryId":"1093","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0019995885800449","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"Mathematics","Score":null,"Total":0}
引用次数: 16
摘要
设P1,…,Pk为一对不相交的简单多边形,共n个顶点,s个起始点。一般来说,起始顶点是两个相邻顶点的x坐标都较大的顶点。我们提出了一种在时间O(n + s log s)内三角化P1,…,Pk的算法。s可以被视为非凸性的度量。特别地,s总是以凹角的数量+ 1为界,并且通常要小得多。我们还描述了三角测量的两种新应用。给定一个平面的关于k对不相交简单多边形的三角剖分,那么这个集合与一个凸多边形Q的交点可以根据k + 1个多边形的顶点总数在时间线性上计算出来。这样的结果只对两个凸多边形是已知的。另一个应用改进了一个多边形可以分解成凸部分的数目的界限。
Fast triangulation of the plane with respect to simple polygons
Let P1,…, Pk be pairwise non-intersecting simple polygons with a total of n vertices and s start vertices. A start vertex, in general, is a vertex both of which neighbors have larger x coordinate. We present an algorithm for triangulating P1,…, Pk in time O(n + s log s). s may be viewed as a measure of non-convexity. In particular, s is always bounded by the number of concave angles + 1, and is usually much smaller. We also describe two new applications of triangulation. Given a triangulation of the plane with respect to a set of k pairwise non-intersecting simple polygons, then the intersection of this set with a convex polygon Q can be computed in time linear with respect to the combined number of vertices of the k + 1 polygons. Such a result had only be known for two convex polygons. The other application improves the bound on the number of convex parts into which a polygon can be decomposed.