说明：  克鲁斯卡尔(Kruskal)算法 （1）算法思想（2）算法特点（3）Kruskal算法的抽象描述（4）用Kruskal算法构造最小生成树的过程（5）算法分析
( Kruse Cull (Kruskal) the algorithm (1) the algorithm thought (2) the algorithm characteristic (3) the Kruskal algorithm abstract description (4) slightly produces tree s process with the Kruskal algorithm structure (5) the algorithmic analysis )