HDU 4640 Island and study-sister（状态压缩）

int g[N][N],n,m,K,st;
int f[1<<N][N],dp[4][1<<N];
int f1[1<<N];


struct node
{
    int st,x;
    
    node(){}
    node(int _st,int _x)
    {
        st=_st;
        x=_x;
    }
};


int visit[1<<N][N];


void init()
{
    int i,j,k;
    FOR0(i,(1<<n)) FOR0(j,n) f[i][j]=INF,visit[i][j]=0;
    f[1][0]=0;
    queue<node> Q;
    Q.push(node(1,0));
    
    while(!Q.empty())
    {
        node u=Q.front();
        Q.pop();
        
        visit[u.st][u.x]=0;
        FOR0(i,n) if(f[u.st|(1<<i)][i]>f[u.st][u.x]+g[u.x][i])
        {
            f[u.st|(1<<i)][i]=f[u.st][u.x]+g[u.x][i];
            if(!visit[u.st|(1<<i)][i])
            {
                visit[u.st|(1<<i)][i]=1;
                Q.push(node(u.st|(1<<i),i));
            }
        }
    }
    FOR0(i,(1<<n)) f1[i]=INF;
    FOR0(i,(1<<n)) FOR0(j,n) upMin(f1[i],f[i][j]);
    
    FOR0(i,4) FOR0(j,(1<<n)) dp[i][j]=INF;
    FOR0(i,(1<<n)) dp[1][i]=f1[i];
    for(i=2;i<=3;i++) for(j=0;j<(1<<n);j++)
    {
        k=j;
        while(k)
        {
            upMin(dp[i][j],max(dp[1][k|1],dp[i-1][(j^k)|1]));
            k=(k-1)&j;
        }
    }
}




int main()
{
    int num=0;
    rush()
    {
        RD(n,m);
        int i,j,k,w;
        FOR0(i,n) FOR0(j,n) g[i][j]=INF;
        FOR0(i,n) g[i][i]=0;
        FOR0(i,m)
        {
            RD(j,k,w);j--;k--;
            if(g[j][k]>w) g[j][k]=g[k][j]=w;
        }
        st=1;
        RD(K);
        FOR0(i,K) RD(j),j--,st|=1<<j;
        printf("Case %d: ",++num);
        init();
        int ans=INF;
        FOR1(i,3) FOR0(j,(1<<n)) if((j&(st))==st)
        {
            upMin(ans,dp[i][j]);
        }
        if(ans==INF) ans=-1;
        PR(ans);
    }
}