1 #include<iostream> 2 #include<cmath> 3 #include<algorithm> 4 #include<cstdio> 5 using namespace std; 6 #define maxn 105 7 int par[maxn]; 8 int n,m; 9 int len;10 struct node11 {12     int x;13     int y;14     int w;//这道题如果用double 出错，结果全为015 };16 node e[maxn * (maxn - 1) / 2];17 int cmp(const node &a , const node &b)18 {19     return a.w < b.w;20 };21 22 int Find(int x)23 {24     int k,j,r;25     r = x;26     while(par[r] != r)27         r = par[r];28     k = x;29     while(k != r)30     {31         j = par[k];32         par[k] = r;33         k = j;34     }35     return r;36 }37 int Merge(int x,int y)38 {39     int a = Find(x);40     int b = Find(y);41     if(a != b)42     {43         par[a] = par[b];44         return 1;45     }46     return 0;47 }48 void input()49 {50     for(int i = 1; i <= n+5; i++)51         par[i] = i;52     len = 0;53     int sta;54     for(int i = 0; i < n*(n-1)/2; i++)55     {56         scanf("%d%d%d%d",&e[i].x,&e[i].y,&e[i].w,&sta);57         if(sta) e[i].w = 0;58     }59 }60 61 void make()62 {63     int all = n*(n-1)/2;64     sort(e,e + all,cmp);65     int t = n - 1;66     for(int i = 0; t && i < all; i++)67     {68         if(Merge(e[i].x,e[i].y))69         {70             len += e[i].w;71             t--;72         }73     }74 }75 int main()76 {77     freopen("input.txt","r",stdin);78     while(scanf("%d",&n) && n)79     {80         input();81         make();82         printf("%d\n",len);83     }84 85     return 0;86 }