2019ICPC-南昌- E. Bob's Problem

2019ICPC-南昌- E. Bob’s Problem

做法：黑边选完，再选白边。没什么好说的。。

#include
using namespace std;
#define int long long
const int maxn=1e6+7;
struct edge
{
    int u,v,w,id;
    bool operator < (edge a)const{
    return w>a.w;
    }
}e[maxn];
int fa[maxn],n,m,k,vis[maxn];
int findfa(int x)
{
    return fa[x]=(fa[x]==x?x:findfa(fa[x]));
}
int eurl()
{
    int cnt=0,ans=0,num=0;
    for(int i=1;i<=m;i++){
        int u=e[i].u,v=e[i].v,w=e[i].w;
        if(e[i].id==1)continue;
        ans+=w;
        int fu=findfa(u),fv=findfa(v);
        if(fu!=fv){
            fa[fu]=fv;
            cnt++;
        }
    }
    for(int i=1;i<=m;i++){
        int u=e[i].u,v=e[i].v,w=e[i].w;
        if(e[i].id==0)continue;
        int fu=findfa(u),fv=findfa(v);
        if(fu!=fv){
            fa[fu]=fv;
            cnt++;
            ans+=w;
            num++;
            vis[i]=1;
            if(num>=k){
                return cnt==n-1?ans:-1;
            }
        }
    }
    for(int i=1;i<=m;i++){
        if(e[i].id==1 && num<k){
            if(vis[i]==0)ans+=e[i].w,num++;
        }
    }
    return cnt==n-1?ans:-1;
}
signed main() {
    long long l,r,s;
    int t;
    scanf("%lld",&t);
    while(t--) {
        //memset(vis,0,sizeof(vis));
        scanf("%lld%lld%lld",&n,&m,&k);
        for(int i=1;i<=n;i++){
            fa[i]=i;
            vis[i]=0;
        }
        for(int i=1;i<=m;i++){
            int a,b,c,d;
            scanf("%lld%lld%lld%lld",&a,&b,&c,&d);
            e[i]=edge{a,b,c,d};
        }
        sort(e+1,e+1+m);
        int ans=eurl();
        printf("%lld\n",ans);
    }

    return 0;
}