POJ 2784 Buy or Build 最小生成树

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枚举方案后做最小生成树。

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const int maxn=1100;const int maxm=10000;int n,q;vector<int>g[10];int c[10];struct Point{    int x,y;    int getValueTo(Point p){        return (p.x-x)*(p.x-x)+(p.y-y)*(p.y-y);    }}p[maxn];struct EDGE{    int u,v,d;    bool operator<(const EDGE& rhs) const{        return d<rhs.d;    }}e[maxn*maxn];int edge;int pa[maxn];void makeset(int n){    for (int i=0;i<=n;i++) pa[i]=i;}int findset(int x){    if (x!=pa[x]) pa[x]=findset(pa[x]);    return pa[x];}bool unionset(int x,int y){    x=findset(x);    y=findset(y);    if (x!=y) {        pa[x]=y;        return true;    }    return false;}int kruskal(){    int ans=0;    for (int i=0;i<edge;i++){        if (unionset(e[i].u,e[i].v)){            ans+=e[i].d;        }    }    return ans;}int main(){while (~scanf("%d%d",&n,&q)){        for (int i=0;i<q;i++){            int cnt;            scanf("%d%d",&cnt,&c[i]);            for (int j=0;j<cnt;j++){                int tmp;                scanf("%d",&tmp);                g[i].push_back(tmp);            }        }        for (int i=1;i<=n;i++) scanf("%d%d",&p[i].x,&p[i].y);        edge=0;        for (int i=1;i<=n;i++){            for (int j=i+1;j<=n;j++){                e[edge].u=i;                e[edge].v=j;                e[edge++].d=p[i].getValueTo(p[j]);            }        }        sort(e,e+edge);        makeset(n);        int ans=kruskal();        for (int s=1;s<(1<<q);s++){            makeset(n);            int cost=0;            for (int i=0;i<q;i++){                if (s&(1<<i)){                    cost+=c[i];                    for (int j=1;j<sz(g[i]);j++){                        unionset(g[i][j-1],g[i][j]);                    }                }            }            ans=min(ans,cost+kruskal());        }        printf("%d\n",ans);}return 0;}

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