生成树木

Question

我正在尝试在给定某些图形边缘（可以将其视为网络）的情况下生成有效树。以下是从文件中读取图形边缘的代码;

    FILE *fin = fopen("somefile.txt", "r");

    for (int i = 0; i <=edges; i++) {
    fscanf(fin, "%d%d%d", &u, &v, &w);
            graph[u][v]=w;
    }
    fclose(fin);

现在我想为给定的根u生成最大数量的可能树（或拓扑），并给定这些边缘的给定大小N。

例如，如果有边缘; 1 ---＆gt; 2; 1 ---＆gt; 3; 3 ---→4。现在如果N是1; u = 1的可能树是1 ----> 2和1 ---> 3。如果N是2，那么可能的树是1 ---> 2＆amp; 3或1 ---＆gt; 3 ----＆gt; 4 实现这一目标的最佳方式是什么？我不关心复杂性问题。我很感激你的帮助！

Answer 1

它可能不是最佳实施但是 这样的事情应该有效

map<vertex,list<edge>> vertexToedgeThatIncludeIt
void Coloredge(edgeList)
{
  for each edge in list:
     edge.color=True
}


void init()
{
   for each edge:
   {
    vertexToedgeThatIncludeIt[edge.vertex1].append(edge)
    vertexToedgeThatIncludeIt[edge.vertex2].append(edge)
   }
}

edge* findUnColoredvertex(edgeList,startPoistion,founfAt)
{
    skip to startPoistion
    for each edge In edgeList:
          if edge not colored return edge 
    update founfAt
    return NULL
}

void spanTree(vertexToedgeThatIncludeIt,spanTreeList,lastvertex)
{
   if(spanTreeList.size==NumberOfTotalvertex)
   {
        print spanningTree
        return 
   }
   nextedge=findUnColoredvertex(vertexToedgeThatIncludeIt[lastvertex],0,founfAt)
   while(nextedge!=NULL)
   {           
       spanTreeList.append(nextedge);
       Coloredge(vertexToedgeThatIncludeIt[lastvertex]);
       spanTree(vertexToedgeThatIncludeIt,spanTreeList,nextedge.othervertex)
       spanTreeList.pop();
       UnColoredge(vertexToedgeThatIncludeIt[lastvertex])
       nextedge=findUnColoredvertex(vertexToedgeThatIncludeIt[lastvertex],founfAt,founfAt)
   }

 }