題目連結：

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
using namespace std;
#define maxn 10010
int father[110];
struct node{
    int x,y,z,d;
}a[maxn],b[maxn],c[maxn];
bool cmp(node a,node b)
{
    return a.z<b.z;
}
void init(int n)
{
    for(int i=1;i<=n;i++)
        father[i]=i;
}
int findFather(int x)
{
    int a=x;
    while(x!=father[x])
    {
        x=father[x];
    }
    while(a!=father[a])
    {
        int z=a;
        a=father[a];
        father[z]=x;
    }
    return x;
}
void Union(int a,int b)
{
    int faA=findFather(a);
    int faB=findFather(b);
    if(faA!=faB)
        father[faA]=faB;
}
int main()
{
    int n;
    while(~scanf("%d",&n)&&n!=0)
    {
        init(n);
        int m=n*(n-1)/2;
        int num1=0;
        for(int i=0;i<m;i++)
        {
            scanf("%d%d%d%d",&a[i].x,&a[i].y,&a[i].z,&a[i].d);
            if(a[i].d==1)
            {
                Union(a[i].x,a[i].y);
            }
            else //if(a[i].d==0)
            {
               // num1++;
                b[num1].x=a[i].x;
                b[num1].y=a[i].y;
                b[num1].z=a[i].z;
                //b[num1].d=a[i].d;
               num1++;
            }
        }
        sort(b,b+num1,cmp);
        int cnt=0;
        for(int i=0;i<num1;i++)
        {
            if(findFather(b[i].x)!=findFather(b[i].y))
            {
                Union(b[i].x,b[i].y);
                cnt+=b[i].z;
            }
        }
        printf("%d\n",cnt);
    }
    return 0;
}