克鲁斯卡尔

#define maxn 100
#define maxm 5000
struct edge
{
    int u,v;
    double w;
}edges[maxm];
int parent[maxm];
int u,v,i,j;
void ufset()
{
    memset(parent,-1,sizeof(parent));
}
int find(int x)
{
    int s;
    for(s=x;parent[s]>=0;s=parent[s])
        ;
    while(s!=x)
    {
        int tmp=parent[x];
        parent[x]=s;
        x=tmp;
    }
    return s;
}
void union(int R1,int R2)
{
    int r1=find(R1),r2=find(R2);
    int tmp=parent[r1]+parent[r2];
    if(parent[r1]>parent[r2])
    {
        parent[r1]=r2;
        parent[r2]=tmp;
    }
    else
    {
        parent[r2]=r1;
        parent[r1]=tmp;
    }
}
bool cmp(edge aa,edge bb)
{
    return aa.w<bb.w;
}
int kruskal()
{
    double sumweight;
    int num=0;
    ufset();
    for(i=0;i<m;++i)
    {
        u=edges[i].u;    v=edges[i].v;
        if(find(u)!=find(v))
        {
            sumweight+=edges[i].w; num++;
            union(u,v);
        }
        if(num>=n-1) break;
    }
    return sumweight;
}