Graph 平面图生成:欧拉公式不适用吗?
我试图建立一些平面图生成算法。我读了很多关于这个主题的资料,她的结果如下:Graph 平面图生成:欧拉公式不适用吗?,graph,Graph,我试图建立一些平面图生成算法。我读了很多关于这个主题的资料,她的结果如下: public Graph graph; ... public Level(int numPoints, int numEdges, int levelID, int timeLim) { this.graph = new Graph(numPoints, numEdges); this.graph.GeneratePlanarGraph(); ... } **Here i w
public Graph graph;
...
public Level(int numPoints, int numEdges, int levelID, int timeLim)
{
this.graph = new Graph(numPoints, numEdges);
this.graph.GeneratePlanarGraph();
...
}
**Here i wrote some functions that build planar graph...**
public void GeneratePlanarGraph() {
if(this.edges_num < this.vertices_num) {
System.out.println("erroe: number of edges mast be\n "+
"bigger than number of vertices\n");
return;
}
int edges = 0;
// add vertices to graph
for(int i = 0 ; i < this.vertices_num ; i++)
this.AddVertex(i+1);
// connect all vertices to circular list
// ( from each vertex 2 connections )
for(int i = 1 ; i <= this.vertices_num ; i++) {
if(i < this.vertices_num) this.AddEdge(i, i+1);
else this.AddEdge(i, 1);
edges++;
}
//connect other edges if its exist
int step = 2;
while(edges < this.edges_num) {
for(int i = 1 ; i <= this.vertices_num ; i++) {
if(i + step <= this.vertices_num) {
this.AddEdge(i, i + step);
edges++;
if(edges == this.edges_num) break;
}
else {
this.AddEdge(i, (i + step) - this.vertices_num);
edges++;
break;
}
}
step++;
}
}
公共图形;
...
公共级别(int numPoints、int numEdges、int levelID、int timeLim)
{
this.graph=新图形(numPoints、numEdges);
this.graph.GeneratePlanarGraph();
...
}
**这里我写了一些函数来构建平面图**
public void GeneratePlanarGraph(){
if(this.edges\u num 对于(int i=1;i首先,请确保,欧拉公式仍然成立
我发现您的算法存在一些问题(除了样式):
- 对于奇数V(顶点数)和足够高的E(边数),它不起作用;更准确地说:对于V=2k+1和E>=2V,生成的图形将不是平面的
- 对于E>2V,它不会像预期的那样工作。根据
AddEdge
的操作,它将生成一个在相同顶点之间具有更多边的多重图,或者生成一个边少于所需边的图
- 它只产生(在它工作的情况下)一个非常特殊的平面图类,在我看来,不是一个非常有趣的类
for(int i = 0 ; i < 100 ; i++)
{
levels[i] = new Level(numPoints, numEdges, levelID, timeLim);
}