HDU 1879（最小生成树）

#include "iostream"
#include "algorithm"
#include "cstdio"
using namespace std;
const int maxn=;
typedef struct
{
    int a,b,v,c;
}node;
int ans;
node graph[maxn*(maxn-)/];
int father[maxn];
int Find(int x)
{
    if(father[x]==x)
        return x;
    else
    {
        father[x]=Find(father[x]);
        return father[x];
    }
}
void Union(int a,int b,int v,int c)
{
    if(Find(a)!=Find(b))
    {
            ans+=v;
            father[Find(a)]=Find(b);
    }
}
bool cmp(node a,node b)
{
    return a.v<b.v;
}
int main()
{
    int N,M;
    while(~scanf("%d",&N)){
        if(N==)
            break;
        M=N*(N-)/;
        ans=;
        for(int i=;i<M;i++)
        {
            scanf("%d%d%d%d",&graph[i].a,&graph[i].b,&graph[i].v,&graph[i].c);
            if(graph[i].c==)
                graph[i].v=;
        }
        for(int i=;i<maxn;i++)
            father[i]=i;
        sort(graph,graph+M,cmp);
        for(int i=;i<M;i++)
            Union(graph[i].a,graph[i].b,graph[i].v,graph[i].c);
        printf("%d\n",ans);
}
    return ;
}