关于最小生成树中的kruskal算法中判断两个点是否在同一个连通分量的方法总结

最开始的方法为：

                   int fa[MAXNODENUM];//MAXNODENUM为节点的数量

                   for(i=1;i<=MAXNODENUM;i++)//节点编号从1开始

                   {fa[i]=-1;}//对fa[]进行初始化

                   int findfa(int v)

                       {int w=v;

                          while(fa[w]>-1)

                              w=fa[w];

                          return w;

                        }

 

                   int fv1=findfa(v1);

                   int fv2=findfa(v2);

                   if(fv1!=fv2)

                    {fa[fv1]=fv2;

                      ................

                     }

 

 

                           

                  方法改进：由于上述方法每一次都要从若干次的循环

                     for(i=1;i<=MAXNUMNODE;i++)

                        {fa[i]=-1;}

                    int findfa(int v)

                         {if(fa[v]>-1)

                           fa[v]=findfa(fa[v]);

                           else

                            return v;

                            return fa[v];

                           }

 

               方法三：

                  for(i=1;i<=MAXNUMNODE;i++)
                      {fa[i]=i;}

                  int findfa(int v)

                       {if(v!=fa[v])

                          fa[v]=findfa(fa[v]);

                          return fa[v];

                        }