克鲁斯卡尔算法

//每次选择最短的边，同时保证边的两个端点并不相连（判断相连可用并查集），之前先排序

typedef struct s
{

    int a;
    int b;
    int c;
}s;
s w[101];
int pre[101];
int  find(int i)
{
int temp,j=i;
while (pre[i]!=i)
{
    i=pre[i];
}
while (j!=i)
{
    temp=pre[j];
    pre[j]=i;
    j=temp;


}
return i;
}
int  merge(int c,int d)
{

    int t1,t2;
    t1=find(c);
    t2=find(d);
    if (t1!=t2)
    {
    pre[t2]=t1;
    return 1;
    }
    return 0;

}
void quicksort(int left,int right)
{

    int low=left;
    int high=right;
    s temp=w[left];
    int key=w[left].c;
    if (left=key))
                high--;
            w[low]=w[high];
            while ((low
 int main()
    {
             int i,n,m,count=0,sum=0;
             scanf("%d%d",&n,&m);
              for (i=1;i<=m;i++)
                scanf("%d%d%d",&w[i].a,&w[i].b,&w[i].c);
                quicksort(1,m);
                for (i=1;i<=n;i++)
                    pre[i]=i;
                for (i=1;i<=m;i++)
                {
                if (merge(w[i].a,w[i].b))//如果不相连
                    {
                    count++;
                    sum+=w[i].c;
                    }

                if (count==n-1)
                    break;
                }
                printf("%d\n",sum);
                return 0;
    }