hdu1879

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
const int _max = 0x3f3f3f3f;
const int maxn = 111;
int map[maxn][maxn];
bool  visit[maxn];
int dist[maxn];
int n;

void prim()
{
     int sum1 = 0;
     for(int i = 1; i <= n; i++)
        dist[i] = map[1][i];
     dist[1] = 0;
     visit[1] = true;
     for(int i = 1; i < n; i++)
     {
         int min = _max;
         int k;
         for(int j = 1; j <= n; j++)
         {
             if(!visit[j] && min > dist[j])
             {
                 min = dist[j];
                 k = j;
             }
         }
         visit[k] = true;
         sum1 += min;
         for(int j = 1; j <= n; j++)
             if(!visit[j] && dist[j] > map[k][j])
                dist[j] = map[k][j];
     }
     printf("%d\n", sum1);
}

int main()
{
    while(scanf("%d", &n)!=EOF&&n)
    {
        for(int i = 1; i <= n; i++)
            for(int j = 1; j <= n; j++)
            map[i][j] = _max;
        for(int i = 0; i < n*(n-1)/2; i++)
        {
            int u, v, w, x;
            scanf("%d%d%d%d", &u, &v, &w, &x);
            if(x==1) map[u][v] = map[v][u] = 0;
            else map[u][v] = map[v][u] = w;
        }
        memset(visit, false, sizeof(visit));
        prim();
    }
}