UESTC 918 WHITE ALBUM --生成树变形

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
#define N 1007

int fa[N];
int n,m,k;
int res;

struct Edge
{
    int u,v,w;
}G[N*N/2];

int cmp(Edge ka,Edge kb)
{
    return ka.w < kb.w;
}

int findset(int x)
{
    if(x != fa[x])
        fa[x] = findset(fa[x]);
    return fa[x];
}

void Kruskal()
{
    int i,j,cnt = m+k;
    sort(G,G+cnt,cmp);
    for(i=0;i<=n;i++)
        fa[i] = i;
    res = 0;
    for(i=0;i<cnt;i++)
    {
        int u = G[i].u;
        int v = G[i].v;
        int fx = findset(u);
        int fy = findset(v);
        if(fx != fy)
        {
            res += G[i].w;
            fa[fx] = fy;
        }
    }
}

int main()
{
    int i,j,a,b,c,x;
    scanf("%d%d%d",&n,&m,&k);
    for(i=0;i<k;i++)
    {
        scanf("%d",&x);
        G[i].u = x;
        G[i].v = 0;
        G[i].w = 0;
    }
    for(i=k;i<m+k;i++)
    {
        scanf("%d%d%d",&a,&b,&c);
        G[i].u = a;
        G[i].v = b;
        G[i].w = c;
    }
    Kruskal();
    printf("%d\n",res);
    return 0;
}