spoj 368

额   最小生成树 ........

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
struct node
{
    int u,v,len;
    void f(int i, int j, int k)
    {
        u = i, v = j;
        len = k;
    }
    bool operator < (const node &p) const
    {
        return len < p.len;
    }
};
node cc[300020];
int f[1010];
int find(int x)
{
    return f[x] == x ? x : f[x] = find(f[x]);
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int p,n,m;
        scanf("%d%d%d",&p,&n,&m);
        for(int i = 1; i <= n; i++)
            f[i] = i;
        for(int i = 0; i < m; i++)
        {
            int x,y,len;
            scanf("%d%d%d",&x,&y,&len);
            cc[i].f(x, y, len);
        }
        sort(cc, cc+m);
        int ans = 0;
        for(int i = 0; i < m; i++)
        {
            int x = find(cc[i].u), y = find(cc[i].v);
            if(x != y)
            {
                ans += cc[i].len;
                f[x] = y;
            }
        }
        printf("%d\n",ans*p);
    }
    return 0;
}