最小生成树之Kruskal算法

问题：关键还是定义数据结构问题，还有如何把两个集合合并成一个。

代码：

#include <iostream>
#include <cstdlib>
using namespace std;

#define MAXV 20
#define INFINITY 65535
typedef struct node
{
	int from;
	int to;
	int weight;
}WGraph;
typedef struct map
{
	WGraph arr[MAXV];
	int vexs,edges;
}*Map;

void createGraph(Map &map)                          //创建图
{
	int i;
	cout<<"please input the edges and vexs:";
	cin>>map->edges>>map->vexs;
	for(i=0;i<map->edges;i++)
	{
		cout<<"please input from,to,weight of graph:";
		cin>>map->arr[i].from>>map->arr[i].to>>map->arr[i].weight;
	}
}

void showGraph(Map wg)
{
    int i;
	cout<<"the num of edges and vexs:";
	cout<<wg->edges<<"   "<<wg->vexs<<endl;
	for(i=0;i<wg->edges;i++)
	{
		cout<<"("<<wg->arr[i].from<<","<<wg->arr[i].to<<"   "<<wg->arr[i].weight<<")"<<endl;
	}
	cout<<endl;
}

void MST_Kruskal(Map map)
{
	int set[MAXV];
	int min;
	int i,j,k,s;
	int temp;
	int flag;                                 //访问标志
	for(i=0;i<map->edges;i++)
	{
		set[i]=i;
	}
	for(j=0;j<map->vexs-1;j++)   //共有n-1条边
	{
		min=INFINITY;
		for(k=0;k<map->edges;k++)                                //查找最小边
		{
			if(set[map->arr[k].from]!=set[map->arr[k].to])
			{
				if(map->arr[k].weight<min)
				{
				min=map->arr[k].weight;
				temp=k;
				}
			}	
		}
		flag=set[map->arr[temp].to];
		for(s=0;s<map->edges;s++)                        //把两个集合合并成一个集合
		{
			if(set[s]==flag)
				set[s]=set[map->arr[temp].from];
		}
		cout<<"("<<map->arr[temp].from<<","<<map->arr[temp].to<<","<<map->arr[temp].weight<<")"<<endl;    //输出最小生成树

	}

}

int main()
{
	Map map;
	map=(Map)malloc(MAXV*sizeof(struct map));
	cout<<"create the map:"<<endl;
	createGraph(map);
	cout<<"output the map";
	showGraph(map);
	cout<<"mst_kruskal :"<<endl;
	MST_Kruskal(map);
	cout<<endl;
	return 0;
}

 运行截图：